The α ↔ β phase transitions of Zn₂P₂O₇ revisited: existence of an additional intermediate phase with an incommensurately modulated structure

Zn₂P₂O₇ crystallizes in a thortveitite-like structure and features temperature-dependent polymorphism. At high temperatures (T > 500 K), the aristotype phase β-Zn₂P₂O₇ (C2/m, Z = 2, a ≃ 6.60, b ≃ 8.28, c ≃ 4.53 Å, β ≃ 105.4°) is stable. At lower temperatures the lock-in phase α₁-Zn₂P₂O₇ [at 350 K: I2/c, Z = 12, a = 20.1131 (13), b = 8.2769 (6), c = 9.109 (3) Å, β = 106.338 (16)°], a sixfold superstructure with commensurate modulation vector q = (1/3, 0, 1/2), is stable. Between the stability ranges of the α₁- and β-phases exists the intermediate, incommensurately modulated α₂-Zn₂P₂O₇ phase with modulation wavevector q ≃ (0.33, 0, 0.40) and C2/m(α, 0, γ)0s superspace group symmetry. The α₁ → α₂ lock-in phase transition at T_L = 408 K is of first-order and features virtually no hysteresis. It is immediately followed by the second-order α₂ → β transition to the non-modulated phase at T_I ≃ 430 K. This transformation is sluggish and even at T = 500 K very weak satellite reflections of the α₂-phase were observed. Both phase transitions were analyzed with differential scanning calorimetry and high-temperature powder and single-crystal X-ray diffraction. The crystal structures of the α₁- and α₂-phases were refined from single crystal data collected at T = 350, 400, 405, 410, 415, 420, 425, 430, 450 and 500 K. Different models describing the slow transition from the incommensurately modulated α₂- to the non-modulated β-phase were tested. In the model resulting in the best residuals, the bridging O atom of the [P₂O₇] group, which is located on a 2/m position in the basic structure, is described as an overlap of an atom ordered in internal space and one atom disordered around the mirror plane. The occupancy of the ordered atom decreases with temperature until at T = 500 K virtually only the disordered atom remains. Simultaneously, the amplitude of the modulation functions of the remaining atoms decreases, so that the T = 500 K structure can be considered as the C2/m aristotype structure, although the diffraction pattern still features satellite reflections of first order with very low intensities.

Computing details

Data collection: APEX2 (Bruker, 2012) for alpha2_zn2p2o7_400, alpha2_zn2p2o7_405, alpha2_zn2p2o7_410, alpha2_zn2p2o7_415, alpha2_zn2p2o7_420, alpha2_zn2p2o7_430, alpha2_zn2p2o7_450, alpha2_zn2p2o7_500. Cell refinement: SAINT-Plus (Bruker, 2012) for alpha2_zn2p2o7_400, alpha2_zn2p2o7_405, alpha2_zn2p2o7_410, alpha2_zn2p2o7_415, alpha2_zn2p2o7_420, alpha2_zn2p2o7_430, alpha2_zn2p2o7_450, alpha2_zn2p2o7_500. Data reduction: SAINT-Plus (Bruker, 2012) for alpha2_zn2p2o7_400, alpha2_zn2p2o7_405, alpha2_zn2p2o7_410, alpha2_zn2p2o7_415, alpha2_zn2p2o7_420, alpha2_zn2p2o7_430, alpha2_zn2p2o7_450, alpha2_zn2p2o7_500. Program(s) used to solve structure: by isomorphous structure methods for alpha2_zn2p2o7_400, alpha2_zn2p2o7_405, alpha2_zn2p2o7_410, alpha2_zn2p2o7_415, alpha2_zn2p2o7_420, alpha2_zn2p2o7_430, alpha2_zn2p2o7_450, alpha2_zn2p2o7_500. Program(s) used to refine structure: JANA2006 (Petříček, et al., 2006) for alpha2_zn2p2o7_400, alpha2_zn2p2o7_405, alpha2_zn2p2o7_410, alpha2_zn2p2o7_415, alpha2_zn2p2o7_420, alpha2_zn2p2o7_430, alpha2_zn2p2o7_450, alpha2_zn2p2o7_500. Molecular graphics: ATOMS (Dowty, 2006) for alpha2_zn2p2o7_400, alpha2_zn2p2o7_405, alpha2_zn2p2o7_410, alpha2_zn2p2o7_415, alpha2_zn2p2o7_420, alpha2_zn2p2o7_430, alpha2_zn2p2o7_450, alpha2_zn2p2o7_500.

(alpha1_zn2p2o7)

Crystal data

O7P2Zn2	F(000) = 1752
Mr = 304.7	Dx = 4.171 Mg m^−3
Monoclinic, I2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -I 2yc	Cell parameters from 9829 reflections
a = 20.1131 (13) Å	θ = 3.4–35.0°
b = 8.2769 (6) Å	µ = 10.53 mm^−1
c = 9.109 (3) Å	T = 350 K
β = 106.338 (16)°	Triangular fragment, clear colourless
V = 1455.2 (5) Å^3	0.45 × 0.33 × 0.03 mm
Z = 12

Data collection

Bruker KAPPA APEX II CCD diffractometer	3215 independent reflections
Radiation source: X-ray tube	2822 reflections with I > 3σ(I)
Graphite monochromator	Rint = 0.037
ω and φ scans	θmax = 35.0°, θmin = 2.1°
Absorption correction: multi-scan SADABS	h = −32→32
Tmin = 0.022, Tmax = 0.73	k = −13→13
46498 measured reflections	l = −14→14

Refinement

Refinement on F	0 constraints
R[F^2 > 2σ(F^2)] = 0.016	Weighting scheme based on measured s.u.'s w = 1/(σ^2(F) + 0.0001F^2)
wR(F^2) = 0.023	(Δ/σ)max = 0.002
S = 1.47	Δρmax = 0.82 e Å^−3
3215 reflections	Δρmin = −0.87 e Å^−3
151 parameters	Extinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)
0 restraints	Extinction coefficient: 4210 (70)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Zn1	0.318103 (6)	0.189033 (13)	0.023504 (13)	0.00927 (4)
Zn2	0.512812 (6)	−0.311694 (13)	0.477093 (13)	0.00847 (4)
Zn3	0.336359 (5)	−0.183166 (14)	−0.001330 (12)	0.00808 (4)
P1	0.433584 (11)	0.01883 (3)	0.29562 (3)	0.00537 (6)
P2	0.261362 (11)	0.48226 (3)	−0.20166 (3)	0.00510 (6)
P3	0.398295 (12)	0.49306 (3)	−0.28479 (3)	0.00592 (6)
O31	0.44822 (4)	−0.13908 (9)	0.37880 (9)	0.0138 (2)
O32	0.41750 (4)	0.15581 (9)	0.39221 (8)	0.00823 (18)
O33	0.26469 (4)	0.64249 (9)	−0.11770 (8)	0.00883 (18)
O34	0.24690 (4)	0.34051 (8)	−0.10924 (8)	0.00868 (18)
O35	0.38337 (4)	0.64524 (9)	−0.37560 (9)	0.0165 (2)
O36	0.40633 (4)	0.34861 (9)	−0.38204 (8)	0.00815 (18)
O21	0.5	0.08403 (13)	0.25	0.0134 (3)
O22	0.33546 (4)	0.44334 (10)	−0.21952 (9)	0.0158 (2)
O11	0.37651 (4)	0.00583 (8)	0.14465 (8)	0.00797 (17)
O12	0.21052 (4)	0.49030 (8)	−0.36065 (7)	0.00839 (17)
O13	0.45958 (4)	0.50579 (8)	−0.14125 (7)	0.00795 (17)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn1	0.01028 (6)	0.00581 (6)	0.00959 (6)	0.00013 (3)	−0.00070 (4)	−0.00005 (3)
Zn2	0.00869 (6)	0.00575 (6)	0.00966 (6)	−0.00011 (3)	0.00044 (4)	−0.00010 (3)
Zn3	0.00808 (6)	0.00605 (6)	0.00953 (6)	0.00048 (3)	0.00154 (5)	0.00005 (3)
P1	0.00512 (9)	0.00516 (9)	0.00538 (9)	0.00050 (7)	0.00075 (8)	−0.00052 (7)
P2	0.00533 (9)	0.00520 (9)	0.00475 (9)	0.00028 (7)	0.00140 (7)	−0.00006 (7)
P3	0.00591 (9)	0.00550 (9)	0.00550 (9)	0.00145 (7)	0.00022 (7)	−0.00097 (7)
O31	0.0176 (3)	0.0076 (3)	0.0130 (3)	0.0036 (3)	−0.0010 (3)	0.0031 (3)
O32	0.0097 (3)	0.0072 (3)	0.0084 (3)	−0.0011 (2)	0.0035 (2)	−0.0031 (2)
O33	0.0102 (3)	0.0066 (3)	0.0100 (3)	−0.0018 (2)	0.0034 (2)	−0.0035 (2)
O34	0.0107 (3)	0.0068 (3)	0.0087 (3)	0.0014 (2)	0.0031 (2)	0.0031 (2)
O35	0.0221 (4)	0.0082 (3)	0.0140 (3)	0.0043 (3)	−0.0033 (3)	0.0022 (3)
O36	0.0086 (3)	0.0075 (3)	0.0088 (3)	−0.0010 (2)	0.0032 (2)	−0.0040 (2)
O21	0.0073 (4)	0.0164 (5)	0.0184 (5)	0	0.0065 (4)	0
O22	0.0089 (3)	0.0228 (4)	0.0179 (3)	0.0017 (3)	0.0071 (3)	−0.0019 (3)
O11	0.0085 (3)	0.0071 (3)	0.0063 (3)	0.0005 (2)	−0.0014 (2)	−0.0007 (2)
O12	0.0109 (3)	0.0073 (3)	0.0052 (3)	0.0012 (2)	−0.0007 (2)	0.0000 (2)
O13	0.0080 (3)	0.0076 (3)	0.0065 (3)	0.0008 (2)	−0.0010 (2)	−0.0012 (2)

Geometric parameters (Å, º)

Zn1—O33^i	2.1123 (9)	Zn3—O11	2.0648 (9)
Zn1—O34	2.0275 (9)	Zn3—O12^iii	2.0860 (9)
Zn1—O35^ii	1.9419 (8)	P1—O31	1.4979 (8)
Zn1—O11	2.0416 (8)	P1—O32	1.5245 (9)
Zn1—O12^iii	2.0627 (10)	P1—O21	1.6002 (5)
Zn2—O31	1.9688 (8)	P1—O11	1.5272 (11)
Zn2—O32^iv	2.0268 (9)	P2—O33	1.5230 (8)
Zn2—O36^v	2.0688 (9)	P2—O34	1.5191 (8)
Zn2—O13^vi	2.0879 (10)	P2—O22	1.5773 (9)
Zn2—O13^vii	2.0591 (8)	P2—O12	1.5213 (11)
Zn3—O32^viii	2.1321 (9)	P3—O35	1.4904 (9)
Zn3—O33^ix	2.1034 (8)	P3—O36	1.5235 (9)
Zn3—O34^i	2.1923 (9)	P3—O22	1.5945 (9)
Zn3—O36^vii	2.0436 (8)	P3—O13	1.5276 (10)
Zn3—Zn1—O33^i	88.38 (2)	O11—Zn3—O12^iii	80.62 (3)
Zn3—Zn1—O34	130.20 (2)	O31—P1—O32	113.60 (5)
Zn3—Zn1—O35^ii	130.88 (2)	O31—P1—O21	111.47 (5)
Zn3—Zn1—O11	40.87 (2)	O31—P1—O11	112.64 (4)
Zn3—Zn1—O12^iii	41.55 (2)	O32—P1—O21	103.13 (5)
O33^i—Zn1—O34	81.36 (3)	O32—P1—O11	110.14 (4)
O33^i—Zn1—O35^ii	116.22 (4)	O21—P1—O11	105.12 (4)
O33^i—Zn1—O11	92.55 (3)	O33—P2—O34	112.49 (5)
O33^i—Zn1—O12^iii	93.92 (3)	O33—P2—O22	108.68 (4)
O34—Zn1—O35^ii	96.63 (3)	O33—P2—O12	111.27 (4)
O34—Zn1—O11	169.80 (3)	O34—P2—O22	103.49 (4)
O34—Zn1—O12^iii	90.49 (3)	O34—P2—O12	112.28 (4)
O35^ii—Zn1—O11	93.39 (3)	O22—P2—O12	108.20 (5)
O35^ii—Zn1—O12^iii	149.71 (4)	O35—P3—O36	112.22 (5)
O11—Zn1—O12^iii	81.72 (3)	O35—P3—O22	111.60 (5)
O31—Zn2—O32^iv	93.67 (3)	O35—P3—O13	113.88 (4)
O31—Zn2—O36^v	114.37 (4)	O36—P3—O22	103.84 (4)
O31—Zn2—O13^vi	149.23 (4)	O36—P3—O13	111.09 (4)
O31—Zn2—O13^vii	98.55 (3)	O22—P3—O13	103.42 (5)
O32^iv—Zn2—O36^v	81.07 (3)	Zn2—O31—P1	150.91 (6)
O32^iv—Zn2—O13^vi	92.25 (3)	Zn2^iv—O32—Zn3^vii	99.01 (4)
O32^iv—Zn2—O13^vii	167.42 (3)	Zn2^iv—O32—P1	126.05 (5)
O36^v—Zn2—O13^vi	96.37 (3)	Zn3^vii—O32—P1	130.94 (4)
O36^v—Zn2—O13^vii	91.14 (3)	Zn1^x—O33—Zn3^xi	100.19 (3)
O13^vi—Zn2—O13^vii	78.74 (3)	Zn1^x—O33—P2	115.75 (4)
Zn1—Zn3—O32^viii	92.80 (2)	Zn3^xi—O33—P2	141.04 (5)
Zn1—Zn3—O33^ix	129.52 (2)	Zn1—O34—Zn3^x	99.98 (3)
Zn1—Zn3—O34^i	75.972 (18)	Zn1—O34—P2	126.50 (5)
Zn1—Zn3—O36^vii	134.51 (2)	Zn3^x—O34—P2	127.86 (4)
Zn1—Zn3—O11	40.315 (19)	Zn1^xii—O35—P3	149.70 (6)
Zn1—Zn3—O12^iii	40.99 (2)	Zn2^v—O36—Zn3^viii	100.56 (3)
O32^viii—Zn3—O33^ix	110.33 (3)	Zn2^v—O36—P3	125.72 (4)
O32^viii—Zn3—O34^i	168.77 (3)	Zn3^viii—O36—P3	131.70 (5)
O32^viii—Zn3—O36^vii	79.18 (3)	P1—O21—P1^xiii	140.58 (7)
O32^viii—Zn3—O11	90.10 (3)	P2—O22—P3	148.95 (6)
O32^viii—Zn3—O12^iii	85.33 (3)	Zn1—O11—Zn3	98.82 (3)
O33^ix—Zn3—O34^i	77.83 (3)	Zn1—O11—P1	127.36 (4)
O33^ix—Zn3—O36^vii	94.59 (3)	Zn3—O11—P1	133.79 (4)
O33^ix—Zn3—O11	158.87 (3)	Zn1^iii—O12—Zn3^iii	97.46 (3)
O33^ix—Zn3—O12^iii	95.27 (3)	Zn1^iii—O12—P2	129.06 (4)
O34^i—Zn3—O36^vii	108.45 (3)	Zn3^iii—O12—P2	132.54 (4)
O34^i—Zn3—O11	81.22 (3)	Zn2^xiv—O13—Zn2^viii	101.26 (3)
O34^i—Zn3—O12^iii	86.23 (3)	Zn2^xiv—O13—P3	130.61 (4)
O36^vii—Zn3—O11	94.54 (3)	Zn2^viii—O13—P3	124.74 (4)
O36^vii—Zn3—O12^iii	163.79 (3)

Symmetry codes: (i) −x+1/2, y−1/2, −z; (ii) x, −y+1, z+1/2; (iii) −x+1/2, −y+1/2, −z−1/2; (iv) −x+1, −y, −z+1; (v) −x+1, −y, −z; (vi) −x+1, y−1, −z+1/2; (vii) x, −y, z+1/2; (viii) x, −y, z−1/2; (ix) x, y−1, z; (x) −x+1/2, y+1/2, −z; (xi) x, y+1, z; (xii) x, −y+1, z−1/2; (xiii) −x+1, y, −z+1/2; (xiv) −x+1, y+1, −z+1/2.

(alpha2_zn2p2o7_400) zinc(II) diphosphate(V)

Crystal data

O7P2Zn2	F(000) = 292
Mr = 304.7	Dx = 4.239 Mg m^−3
Monoclinic, C2/m(α0γ)0s†	Mo Kα radiation, λ = 0.71073 Å
q = 0.332680a* + 0.407590c*	Cell parameters from 6552 reflections
a = 6.6082 (2) Å	θ = 3.5–45.2°
b = 8.2821 (3) Å	µ = 10.7 mm^−1
c = 4.5238 (2) Å	T = 400 K
β = 105.4390 (17)°	Rod, translucent colourless
V = 238.65 (2) Å^3	0.42 × 0.30 × 0.06 mm
Z = 2

† Symmetry operations: (1) x₁, x₂, x₃, x₄; (2) −x₁, x₂, −x₃, −x₄+1/2; (3) −x₁, −x₂, −x₃, −x₄; (4) x₁, −x₂, x₃, x₄+1/2; (5) x₁+1/2, x₂+1/2, x₃, x₄; (6) −x₁+1/2, x₂+1/2, −x₃, −x₄+1/2; (7) −x₁+1/2, −x₂+1/2, −x₃, −x₄; (8) x₁+1/2, −x₂+1/2, x₃, x₄+1/2.

Data collection

Bruker KAPPA APEX II CCD diffractometer	5020 independent reflections
Radiation source: X-ray tube	2280 reflections with I > 3σ(I)
Graphite monochromator	Rint = 0.026
ω and φ scans	θmax = 50.3°, θmin = 2.7°
Absorption correction: multi-scan SADABS	h = −13→13
Tmin = 0.025, Tmax = 0.60	k = −16→16
13480 measured reflections	l = −9→5

Refinement

Refinement on F	1 constraint
R[F > 3σ(F)] = 0.026	Weighting scheme based on measured s.u.'s w = 1/(σ^2(F) + 0.0001F^2)
wR(F) = 0.040	(Δ/σ)max = 0.017
S = 1.24	Δρmax = 0.90 e Å^−3
5020 reflections	Δρmin = −0.83 e Å^−3
146 parameters	Extinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)
0 restraints	Extinction coefficient: 1840 (80)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Zn	0.5	0.18921 (3)	1	0.01797 (6)
P	0.78961 (3)	0	0.59052 (4)	0.00896 (4)
O1	0.62199 (8)	0	0.28617 (12)	0.01031 (11)
O2	1	−0.0528 (10)	0.5	0.0240 (10)	0.234 (6)
O2'	1	−0.011 (3)	0.5	0.068 (6)	0.266 (6)
O3	0.78239 (9)	−0.15146 (6)	0.77458 (11)	0.01910 (12)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn	0.02176 (12)	0.00790 (5)	0.01688 (11)	0	−0.00773 (6)	0
P	0.00772 (6)	0.01115 (7)	0.00709 (7)	0	0.00037 (5)	0
O1	0.01022 (17)	0.01108 (17)	0.00771 (17)	0	−0.00095 (13)	0
O2	0.0090 (10)	0.035 (2)	0.0299 (13)	0	0.0086 (9)	0
O2'	0.0090 (13)	0.151 (17)	0.047 (2)	0	0.0122 (14)	0
O3	0.0298 (2)	0.01099 (15)	0.01290 (16)	0.00574 (14)	−0.00059 (15)	0.00268 (12)

Geometric parameters (Å, º)

	Average	Minimum	Maximum
Zn—O1^i	2.0590 (11)	2.0157 (12)	2.0878 (14)
Zn—O1^ii	2.0590 (11)	2.0161 (12)	2.0893 (14)
Zn—O3^iii	2.0192 (16)	1.9550 (17)	2.0858 (18)
Zn—O3^iv	2.0193 (16)	1.9561 (17)	2.0884 (18)
Zn—O3^v	2.372 (2)	2.178 (2)	2.762 (2)
Zn—O3^vi	2.375 (2)	2.178 (2)	2.765 (2)
P—O1	1.5207 (11)	1.5191 (11)	1.5222 (11)
P—O2	1.602 (5)	1.558 (3)	1.624 (3)
P—O2^vii	1.601 (5)	1.558 (3)	1.624 (3)
P—O2'	1.5541 (17)	1.5405 (10)	1.569 (3)
P—O2'^vii	1.5541 (16)	1.5405 (10)	1.569 (3)
P—O3	1.5165 (14)	1.5069 (14)	1.5262 (14)
P—O3^vi	1.5165 (14)	1.5069 (14)	1.5262 (14)
O2—O2'	0.35 (3)	0.26 (3)	0.40 (3)
O2—O2'^vii	0.54 (3)	0.44 (3)	0.59 (3)
O2'—O2'^vii	0.19 (4)	0.19 (4)	0.19 (4)
O1^i—Zn—O1^ii	80.52 (4)	79.71 (4)	81.37 (4)
O1^i—Zn—O3^iii	157.50 (9)	142.27 (11)	169.17 (9)
O1^i—Zn—O3^iv	94.12 (6)	91.25 (7)	95.71 (5)
O1^i—Zn—O3^v	81.42 (6)	74.25 (7)	88.88 (8)
O1^i—Zn—O3^vi	87.04 (6)	79.51 (7)	92.10 (7)
O1^ii—Zn—O3^iii	94.10 (6)	91.32 (7)	95.71 (5)
O1^ii—Zn—O3^iv	157.39 (9)	142.02 (11)	168.96 (9)
O1^ii—Zn—O3^v	87.12 (6)	79.60 (7)	92.17 (7)
O1^ii—Zn—O3^vi	81.34 (6)	74.14 (7)	88.76 (8)
O3^iii—Zn—O3^iv	98.16 (5)	97.18 (5)	99.77 (5)
O3^iii—Zn—O3^v	76.61 (7)	68.03 (7)	82.44 (8)
O3^iii—Zn—O3^vi	113.84 (8)	107.48 (9)	124.79 (9)
O3^iv—Zn—O3^v	113.89 (8)	107.68 (9)	124.98 (9)
O3^iv—Zn—O3^vi	76.56 (7)	67.89 (7)	82.28 (8)
O3^v—Zn—O3^vi	164.83 (5)	163.20 (5)	166.39 (5)
O1—P—O2	104.3 (3)	100.8 (2)	107.5 (3)
O1—P—O2^vii	104.4 (3)	100.8 (2)	107.5 (3)
O1—P—O2'	104.35 (7)	103.54 (7)	105.22 (6)
O1—P—O2'^vii	104.35 (7)	103.54 (7)	105.22 (6)
O1—P—O3	112.02 (6)	111.66 (6)	112.66 (6)
O1—P—O3^vi	112.03 (6)	111.66 (6)	112.66 (6)
O2—P—O2'	12.6 (10)	8.9 (10)	14.4 (10)
O2—P—O2'^vii	19.5 (10)	15.6 (10)	21.4 (10)
O2—P—O3	98.5 (4)	96.3 (5)	99.4 (3)
O2—P—O3^vi	117.0 (3)	115.9 (5)	120.0 (4)
O2^vii—P—O2'	19.4 (10)	15.6 (10)	21.4 (10)
O2^vii—P—O2'^vii	12.5 (10)	8.9 (10)	14.4 (10)
O2^vii—P—O3	116.9 (3)	115.9 (5)	120.0 (4)
O2^vii—P—O3^vi	98.5 (4)	96.3 (5)	99.4 (3)
O2'—P—O2'^vii	7.0 (13)	6.9 (13)	7.0 (13)
O2'—P—O3	104.8 (8)	97.6 (8)	112.2 (8)
O2'—P—O3^vi	110.9 (8)	103.7 (8)	118.2 (8)
O2'^vii—P—O3	110.9 (8)	103.7 (8)	118.2 (8)
O2'^vii—P—O3^vi	104.9 (8)	97.6 (8)	112.2 (8)
O3—P—O3^vi	112.10 (8)	111.92 (8)	112.27 (8)
Zn^viii—O1—Zn^ix	99.40 (7)	98.02 (7)	100.38 (7)
Zn^viii—O1—P	129.67 (4)	127.46 (4)	131.73 (4)
Zn^ix—O1—P	129.66 (4)	127.46 (4)	131.73 (4)
P—O2—P^x	151.0 (8)	148.9 (6)	155.2 (10)
P—O2—O2'	75.5 (8)	70.4 (6)	84.7 (11)
P—O2—O2'^vii	75.5 (6)	73.0 (4)	82.0 (7)
P^x—O2—O2'	75.6 (8)	70.5 (6)	84.9 (11)
P^x—O2—O2'^vii	75.5 (6)	73.0 (4)	82.2 (7)
O2'—O2—O2'^vii	3.6 (9)	0.0 (5)	10 (3)
P—O2'—P^x	173.0 (19)	168.3 (18)	177.8 (19)
P—O2'—O2	92.0 (15)	85.8 (16)	101 (2)
P—O2'—O2^vii	85.0 (12)	81.8 (12)	91.4 (15)
P—O2'—O2'^vii	86.5 (9)	84.0 (9)	89.0 (9)
P^x—O2'—O2	91.9 (15)	85.6 (16)	100 (2)
P^x—O2'—O2^vii	85.1 (12)	81.8 (12)	91.2 (15)
P^x—O2'—O2'^vii	86.5 (9)	84.0 (9)	89.0 (9)
O2—O2'—O2'^vii	170.5 (12)	156 (3)	179.8 (11)
O2^vii—O2'—O2'^vii	6.1 (6)	0.1 (7)	13.7 (9)
Zn^xi—O3—Zn^v	103.31 (8)	97.79 (9)	112.35 (8)
Zn^xi—O3—P	134.34 (11)	125.93 (11)	141.43 (10)
Zn^v—O3—P	119.28 (8)	113.93 (8)	124.37 (9)

Symmetry codes: (i) x₁, x₂, x₃+1, x₄; (ii) −x₁+1, x₂, −x₃+1, −x₄+1/2; (iii) x₁−1/2, x₂+1/2, x₃, x₄; (iv) −x₁+3/2, x₂+1/2, −x₃+2, −x₄+1/2; (v) −x₁+1, −x₂, −x₃+2, −x₄; (vi) x₁, −x₂, x₃, x₄+1/2; (vii) −x₁+2, −x₂, −x₃+1, −x₄; (viii) x₁, x₂, x₃−1, x₄; (ix) −x₁+1, −x₂, −x₃+1, −x₄; (x) −x₁+2, x₂, −x₃+1, −x₄+1/2; (xi) x₁+1/2, x₂−1/2, x₃, x₄.

(alpha2_zn2p2o7_405) zinc(II) diphosphate(V)

Crystal data

O7P2Zn2	F(000) = 292
Mr = 304.7	Dx = 4.240 Mg m^−3
Monoclinic, C2/m(α0γ)0s†	Mo Kα radiation, λ = 0.71073 Å
q = 0.33153(12)a* + 0.40487(8)c*	Cell parameters from 6325 reflections
a = 6.6053 (2) Å	θ = 2.5–45.2°
b = 8.2821 (2) Å	µ = 10.70 mm^−1
c = 4.5243 (1) Å	T = 405 K
β = 105.4163 (14)°	Rod, translucent colourless
V = 238.60 (1) Å^3	0.42 × 0.30 × 0.06 mm
Z = 2

† Symmetry operations: (1) x₁, x₂, x₃, x₄; (2) −x₁, x₂, −x₃, −x₄+1/2; (3) −x₁, −x₂, −x₃, −x₄; (4) x₁, −x₂, x₃, x₄+1/2; (5) x₁+1/2, x₂+1/2, x₃, x₄; (6) −x₁+1/2, x₂+1/2, −x₃, −x₄+1/2; (7) −x₁+1/2, −x₂+1/2, −x₃, −x₄; (8) x₁+1/2, −x₂+1/2, x₃, x₄+1/2.

Data collection

Bruker KAPPA APEX II CCD diffractometer	5038 independent reflections
Radiation source: X-ray tube	2245 reflections with I > 3σ(I)
Graphite monochromator	Rint = 0.025
ω and φ scans	θmax = 45.3°, θmin = 2.1°
Absorption correction: multi-scan SADABS	h = −13→13
Tmin = 0.025, Tmax = 0.60	k = −16→16
13503 measured reflections	l = −9→5

Refinement

Refinement on F	1 constraint
R[F > 3σ(F)] = 0.024	Weighting scheme based on measured s.u.'s w = 1/(σ^2(F) + 0.0001F^2)
wR(F) = 0.038	(Δ/σ)max = 0.037
S = 1.18	Δρmax = 0.96 e Å^−3
5038 reflections	Δρmin = −0.76 e Å^−3
146 parameters	Extinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)
0 restraints	Extinction coefficient: 2180 (80)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Zn	0.5	0.18950 (2)	1	0.01805 (6)
P	0.78950 (3)	0	0.59053 (4)	0.00889 (4)
O1	0.62167 (8)	0	0.28594 (12)	0.01034 (10)
O2	1	−0.0566 (7)	0.5	0.0181 (9)	0.208 (3)
O2'	1	−0.0202 (8)	0.5	0.0332 (18)	0.292 (3)
O3	0.78233 (8)	−0.15128 (5)	0.77488 (10)	0.01919 (11)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn	0.02193 (11)	0.00802 (5)	0.01689 (11)	0	−0.00762 (5)	0
P	0.00760 (6)	0.01115 (7)	0.00713 (7)	0	0.00055 (5)	0
O1	0.01032 (16)	0.01113 (17)	0.00783 (16)	0	−0.00064 (13)	0
O2	0.0067 (8)	0.022 (2)	0.0268 (12)	0	0.0063 (8)	0
O2'	0.0110 (7)	0.043 (5)	0.0494 (17)	0	0.0150 (9)	0
O3	0.0301 (2)	0.01076 (14)	0.01322 (16)	0.00600 (14)	−0.00024 (15)	0.00261 (12)

Geometric parameters (Å, º)

	Average	Minimum	Maximum
Zn—O1^i	2.0595 (11)	2.0109 (12)	2.0888 (14)
Zn—O1^ii	2.0601 (11)	2.0130 (12)	2.0951 (14)
Zn—O3^iii	2.0179 (16)	1.9573 (17)	2.0763 (18)
Zn—O3^iv	2.0187 (16)	1.9607 (17)	2.0856 (18)
P—O1	1.5223 (12)	1.5194 (12)	1.5252 (12)
P—O2	1.611 (5)	1.558 (3)	1.646 (3)
P—O2^v	1.610 (5)	1.558 (3)	1.646 (3)
P—O2'	1.5602 (9)	1.5449 (8)	1.5777 (11)
P—O2'^v	1.5602 (9)	1.5449 (8)	1.5777 (11)
P—O3	1.5157 (14)	1.5038 (14)	1.5254 (14)
P—O3^vi	1.5157 (14)	1.5038 (14)	1.5254 (14)
O2—O2'	0.313 (10)	0.248 (11)	0.351 (9)
O2—O2'^v	0.642 (11)	0.558 (13)	0.686 (9)
O2'—O2'^v	0.335 (10)	0.335 (10)	0.335 (10)
O1^i—Zn—O1^ii	80.38 (4)	79.58 (4)	81.15 (4)
O1^i—Zn—O3^iii	157.50 (9)	142.77 (11)	169.05 (9)
O1^i—Zn—O3^iv	94.19 (6)	91.60 (7)	95.66 (6)
O1^ii—Zn—O3^iii	94.18 (6)	91.86 (7)	95.66 (6)
O1^ii—Zn—O3^iv	157.22 (9)	141.73 (11)	168.24 (9)
O3^iii—Zn—O3^iv	98.19 (5)	97.28 (5)	99.73 (5)
O1—P—O2	104.3 (3)	99.7 (3)	108.8 (3)
O1—P—O2^v	104.4 (3)	99.7 (3)	108.8 (3)
O1—P—O2'	104.31 (6)	103.53 (6)	105.16 (6)
O1—P—O2'^v	104.31 (6)	103.53 (6)	105.16 (6)
O1—P—O3	112.09 (6)	111.81 (6)	112.67 (6)
O1—P—O3^vi	112.10 (6)	111.81 (6)	112.67 (6)
O2—P—O2'	11.1 (4)	8.4 (4)	12.5 (3)
O2—P—O2'^v	23.2 (4)	19.9 (4)	24.9 (3)
O2—P—O3	97.3 (3)	94.1 (4)	98.3 (2)
O2—P—O3^vi	118.1 (3)	116.7 (3)	121.7 (3)
O2^v—P—O2'	23.2 (4)	19.9 (4)	24.9 (3)
O2^v—P—O2'^v	11.1 (4)	8.4 (4)	12.5 (3)
O2^v—P—O3	118.0 (3)	116.7 (3)	121.7 (3)
O2^v—P—O3^vi	97.3 (3)	94.1 (4)	98.3 (2)
O2'—P—O2'^v	12.3 (4)	12.2 (4)	12.4 (4)
O2'—P—O3	102.5 (2)	95.7 (2)	109.4 (2)
O2'—P—O3^vi	113.2 (2)	106.4 (2)	120.1 (2)
O2'^v—P—O3	113.2 (2)	106.4 (2)	120.1 (2)
O2'^v—P—O3^vi	102.5 (2)	95.7 (2)	109.4 (2)
O3—P—O3^vi	111.94 (8)	111.59 (8)	112.29 (8)
Zn^vii—O1—Zn^viii	99.54 (7)	98.12 (8)	100.72 (7)
Zn^vii—O1—P	129.60 (4)	127.56 (3)	131.64 (4)
Zn^viii—O1—P	129.59 (4)	127.56 (3)	131.64 (4)
P—O2—P^ix	148.6 (6)	147.1 (4)	151.5 (7)
P—O2—O2'	74.4 (8)	66.58 (17)	85.8 (8)
P—O2—O2'^v	74.3 (5)	71.3 (3)	80.4 (5)
P^ix—O2—O2'	74.3 (8)	66.51 (17)	85.6 (8)
P^ix—O2—O2'^v	74.3 (5)	71.3 (3)	80.3 (5)
O2'—O2—O2'^v	7.6 (7)	0.2 (7)	19.6 (15)
P—O2'—P^ix	167.7 (5)	163.2 (5)	172.1 (5)
P—O2'—O2	94.5 (15)	85.1 (18)	105.0 (18)
P—O2'—O2^v	82.4 (8)	79.0 (8)	88.8 (9)
P—O2'—O2'^v	83.8 (3)	81.5 (2)	86.2 (3)
P^ix—O2'—O2	94.5 (15)	85.2 (18)	105.1 (18)
P^ix—O2'—O2^v	82.6 (8)	79.1 (8)	88.9 (9)
P^ix—O2'—O2'^v	83.8 (3)	81.5 (2)	86.2 (3)
O2—O2'—O2'^v	165.8 (11)	146.0 (17)	179.6 (13)
O2^v—O2'—O2'^v	6.7 (4)	0.2 (7)	14.4 (3)
Zn^x—O3—P	134.24 (10)	125.54 (11)	140.96 (10)

Symmetry codes: (i) x₁, x₂, x₃+1, x₄; (ii) −x₁+1, x₂, −x₃+1, −x₄+1/2; (iii) x₁−1/2, x₂+1/2, x₃, x₄; (iv) −x₁+3/2, x₂+1/2, −x₃+2, −x₄+1/2; (v) −x₁+2, −x₂, −x₃+1, −x₄; (vi) x₁, −x₂, x₃, x₄+1/2; (vii) x₁, x₂, x₃−1, x₄; (viii) −x₁+1, −x₂, −x₃+1, −x₄; (ix) −x₁+2, x₂, −x₃+1, −x₄+1/2; (x) x₁+1/2, x₂−1/2, x₃, x₄.

(alpha2_zn2p2o7_410) zinc(II) diphosphate(V)

Crystal data

O7P2Zn2	F(000) = 292
Mr = 304.7	Dx = 4.240 Mg m^−3
Monoclinic, C2/m(α0γ)0s†	Mo Kα radiation, λ = 0.71073 Å
q = 0.33062(11)a* + 0.40287(8)c*	Cell parameters from 6378 reflections
a = 6.6041 (2) Å	θ = 2.5–45.2°
b = 8.2827 (2) Å	µ = 10.70 mm^−1
c = 4.5249 (1) Å	T = 410 K
β = 105.4064 (13)°	Rod, translucent colourless
V = 238.62 (1) Å^3	0.42 × 0.30 × 0.06 mm
Z = 2

† Symmetry operations: (1) x₁, x₂, x₃, x₄; (2) −x₁, x₂, −x₃, −x₄+1/2; (3) −x₁, −x₂, −x₃, −x₄; (4) x₁, −x₂, x₃, x₄+1/2; (5) x₁+1/2, x₂+1/2, x₃, x₄; (6) −x₁+1/2, x₂+1/2, −x₃, −x₄+1/2; (7) −x₁+1/2, −x₂+1/2, −x₃, −x₄; (8) x₁+1/2, −x₂+1/2, x₃, x₄+1/2.

Data collection

Bruker KAPPA APEX II CCD diffractometer	5059 independent reflections
Radiation source: X-ray tube	2230 reflections with I > 3σ(I)
Graphite monochromator	Rint = 0.026
ω and φ scans	θmax = 45.4°, θmin = 2.1°
Absorption correction: multi-scan SADABS	h = −13→13
Tmin = 0.025, Tmax = 0.60	k = −16→16
13567 measured reflections	l = −9→5

Refinement

Refinement on F	1 constraint
R[F > 3σ(F)] = 0.024	Weighting scheme based on measured s.u.'s w = 1/(σ^2(F) + 0.0001F^2)
wR(F) = 0.038	(Δ/σ)max = 0.025
S = 1.16	Δρmax = 0.85 e Å^−3
5059 reflections	Δρmin = −0.90 e Å^−3
146 parameters	Extinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)
0 restraints	Extinction coefficient: 2370 (80)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Zn	0.5	0.18943 (2)	1	0.01840 (6)
P	0.78941 (3)	0	0.59057 (4)	0.00902 (4)
O1	0.62166 (8)	0	0.28602 (11)	0.01067 (10)
O2	1	−0.0572 (10)	0.5	0.0193 (10)	0.192 (4)
O2'	1	−0.0215 (9)	0.5	0.035 (2)	0.308 (4)
O3	0.78202 (8)	−0.15135 (5)	0.77490 (10)	0.01933 (11)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn	0.02252 (11)	0.00821 (5)	0.01706 (11)	0	−0.00771 (5)	0
P	0.00772 (6)	0.01148 (7)	0.00710 (6)	0	0.00067 (5)	0
O1	0.01089 (16)	0.01137 (17)	0.00798 (15)	0	−0.00059 (12)	0
O2	0.0073 (9)	0.024 (3)	0.0289 (14)	0	0.0082 (9)	0
O2'	0.0111 (7)	0.052 (6)	0.0476 (15)	0	0.0158 (8)	0
O3	0.0300 (2)	0.01112 (14)	0.01342 (15)	0.00610 (14)	−0.00017 (14)	0.00258 (11)

Geometric parameters (Å, º)

	Average	Minimum	Maximum
Zn—O1^i	2.0598 (11)	2.0107 (12)	2.0975 (14)
Zn—O1^ii	2.0591 (11)	2.0091 (12)	2.0928 (14)
Zn—O3^iii	2.0198 (16)	1.9664 (17)	2.0793 (18)
Zn—O3^iv	2.0188 (16)	1.9642 (17)	2.0729 (18)
P—O1	1.5221 (11)	1.5184 (11)	1.5257 (11)
P—O2	1.612 (6)	1.565 (3)	1.639 (3)
P—O2^v	1.611 (5)	1.565 (3)	1.639 (3)
P—O2'	1.5617 (10)	1.5487 (8)	1.5771 (12)
P—O2'^v	1.5616 (10)	1.5487 (8)	1.5771 (12)
P—O3	1.5162 (13)	1.5064 (14)	1.5228 (13)
P—O3^vi	1.5161 (13)	1.5064 (14)	1.5228 (13)
O2—O2'	0.303 (12)	0.232 (13)	0.341 (11)
O2—O2'^v	0.655 (12)	0.572 (15)	0.697 (11)
O2'—O2'^v	0.356 (10)	0.356 (10)	0.356 (10)
O1^i—Zn—O1^ii	80.44 (4)	79.63 (4)	81.16 (4)
O1^i—Zn—O3^iii	157.26 (9)	142.28 (11)	168.00 (10)
O1^i—Zn—O3^iv	94.17 (6)	92.17 (7)	95.51 (7)
O1^ii—Zn—O3^iii	94.15 (6)	92.00 (7)	95.51 (7)
O1^ii—Zn—O3^iv	157.39 (9)	143.03 (11)	168.58 (9)
O3^iii—Zn—O3^iv	98.25 (5)	97.39 (5)	99.65 (5)
O1—P—O2	104.3 (3)	100.8 (3)	107.6 (3)
O1—P—O2^v	104.3 (3)	100.8 (3)	107.6 (3)
O1—P—O2'	104.28 (6)	103.57 (6)	105.04 (6)
O1—P—O2'^v	104.28 (6)	103.57 (6)	105.04 (6)
O1—P—O3	112.07 (6)	111.79 (6)	112.63 (6)
O1—P—O3^vi	112.08 (6)	111.79 (6)	112.63 (6)
O2—P—O2'	10.8 (4)	8.0 (5)	12.1 (4)
O2—P—O2'^v	23.7 (4)	20.6 (5)	25.2 (4)
O2—P—O3	96.9 (3)	94.3 (4)	97.8 (3)
O2—P—O3^vi	118.6 (3)	117.6 (3)	121.7 (4)
O2^v—P—O2'	23.7 (4)	20.6 (5)	25.2 (4)
O2^v—P—O2'^v	10.7 (4)	8.0 (5)	12.1 (4)
O2^v—P—O3	118.5 (3)	117.6 (3)	121.7 (4)
O2^v—P—O3^vi	96.9 (3)	94.3 (4)	97.8 (3)
O2'—P—O2'^v	13.1 (4)	13.0 (4)	13.2 (4)
O2'—P—O3	102.2 (2)	95.9 (2)	108.6 (2)
O2'—P—O3^vi	113.6 (2)	107.3 (2)	119.9 (2)
O2'^v—P—O3	113.6 (2)	107.3 (2)	119.9 (2)
O2'^v—P—O3^vi	102.2 (2)	95.9 (2)	108.6 (2)
O3—P—O3^vi	111.93 (8)	111.62 (8)	112.23 (8)
Zn^vii—O1—Zn^viii	99.49 (7)	98.05 (8)	100.82 (7)
Zn^vii—O1—P	129.63 (4)	127.78 (3)	131.53 (4)
Zn^viii—O1—P	129.61 (4)	127.78 (3)	131.53 (4)
P—O2—P^ix	148.2 (7)	146.8 (5)	151.3 (9)
P—O2—O2'	74.3 (9)	67.53 (19)	84.6 (9)
P—O2—O2'^v	74.2 (5)	71.8 (4)	79.5 (5)
P^ix—O2—O2'	74.1 (9)	67.34 (19)	84.1 (9)
P^ix—O2—O2'^v	74.1 (5)	71.8 (4)	79.3 (5)
O2'—O2—O2'^v	6.2 (8)	0.0 (5)	16.5 (15)
P—O2'—P^ix	166.9 (5)	162.8 (5)	171.1 (5)
P—O2'—O2	95.0 (17)	87 (2)	104 (2)
P—O2'—O2^v	82.1 (8)	79.4 (9)	87.5 (9)
P—O2'—O2'^v	83.5 (3)	81.3 (3)	85.7 (3)
P^ix—O2'—O2	95.2 (17)	87 (2)	105 (2)
P^ix—O2'—O2^v	82.3 (8)	79.5 (9)	87.6 (9)
P^ix—O2'—O2'^v	83.5 (3)	81.3 (3)	85.7 (3)
O2—O2'—O2'^v	168.9 (12)	152.8 (17)	179.9 (16)
O2^v—O2'—O2'^v	5.0 (4)	0.0 (5)	10.7 (3)
Zn^x—O3—P	134.18 (10)	126.02 (10)	140.35 (10)

Symmetry codes: (i) x₁, x₂, x₃+1, x₄; (ii) −x₁+1, x₂, −x₃+1, −x₄+1/2; (iii) x₁−1/2, x₂+1/2, x₃, x₄; (iv) −x₁+3/2, x₂+1/2, −x₃+2, −x₄+1/2; (v) −x₁+2, −x₂, −x₃+1, −x₄; (vi) x₁, −x₂, x₃, x₄+1/2; (vii) x₁, x₂, x₃−1, x₄; (viii) −x₁+1, −x₂, −x₃+1, −x₄; (ix) −x₁+2, x₂, −x₃+1, −x₄+1/2; (x) x₁+1/2, x₂−1/2, x₃, x₄.

(alpha2_zn2p2o7_415) zinc(II) diphosphate(V)

Crystal data

O7P2Zn2	F(000) = 292
Mr = 304.7	Dx = 4.240 Mg m^−3
Monoclinic, C2/m(α0γ)0s†	Mo Kα radiation, λ = 0.71073 Å
q = 0.33004(12)a* + 0.40167(8)c*	Cell parameters from 6135 reflections
a = 6.6036 (2) Å	θ = 2.4–45.3°
b = 8.2830 (2) Å	µ = 10.70 mm^−1
c = 4.5250 (1) Å	T = 415 K
β = 105.4028 (13)°	Rod, translucent colourless
V = 238.62 (1) Å^3	0.42 × 0.30 × 0.06 mm
Z = 2

† Symmetry operations: (1) x₁, x₂, x₃, x₄; (2) −x₁, x₂, −x₃, −x₄+1/2; (3) −x₁, −x₂, −x₃, −x₄; (4) x₁, −x₂, x₃, x₄+1/2; (5) x₁+1/2, x₂+1/2, x₃, x₄; (6) −x₁+1/2, x₂+1/2, −x₃, −x₄+1/2; (7) −x₁+1/2, −x₂+1/2, −x₃, −x₄; (8) x₁+1/2, −x₂+1/2, x₃, x₄+1/2.

Data collection

Bruker KAPPA APEX II CCD diffractometer	5064 independent reflections
Radiation source: X-ray tube	2147 reflections with I > 3σ(I)
Graphite monochromator	Rint = 0.026
ω and φ scans	θmax = 45.4°, θmin = 2.1°
Absorption correction: multi-scan SADABS	h = −13→13
Tmin = 0.025, Tmax = 0.60	k = −16→16
13588 measured reflections	l = −9→5

Refinement

Refinement on F	1 constraint
R[F > 3σ(F)] = 0.024	Weighting scheme based on measured s.u.'s w = 1/(σ^2(F) + 0.0001F^2)
wR(F) = 0.039	(Δ/σ)max = 0.028
S = 1.16	Δρmax = 0.87 e Å^−3
5064 reflections	Δρmin = −0.82 e Å^−3
146 parameters	Extinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)
0 restraints	Extinction coefficient: 2400 (80)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Zn	0.5	0.18966 (2)	1	0.01864 (6)
P	0.78938 (3)	0	0.59065 (4)	0.00910 (4)
O1	0.62157 (8)	0	0.28621 (11)	0.01072 (10)
O2	1	−0.0561 (12)	0.5	0.0183 (11)	0.178 (4)
O2'	1	−0.0210 (10)	0.5	0.035 (2)	0.322 (4)
O3	0.78182 (8)	−0.15135 (5)	0.77494 (10)	0.01944 (11)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn	0.02279 (12)	0.00831 (5)	0.01731 (12)	0	−0.00782 (6)	0
P	0.00774 (6)	0.01165 (7)	0.00720 (6)	0	0.00072 (5)	0
O1	0.01077 (15)	0.01164 (17)	0.00801 (15)	0	−0.00056 (12)	0
O2	0.0060 (9)	0.024 (3)	0.0266 (14)	0	0.0070 (9)	0
O2'	0.0123 (7)	0.048 (6)	0.0495 (17)	0	0.0160 (9)	0
O3	0.0302 (2)	0.01116 (15)	0.01367 (15)	0.00617 (14)	0.00000 (14)	0.00265 (12)

Geometric parameters (Å, º)

	Average	Minimum	Maximum
Zn—O1^i	2.0612 (13)	2.0128 (14)	2.0977 (16)
Zn—O1^ii	2.0608 (13)	2.0119 (14)	2.0952 (15)
Zn—O3^iii	2.0190 (17)	1.9664 (19)	2.075 (2)
Zn—O3^iv	2.0184 (17)	1.9653 (19)	2.072 (2)
P—O1	1.5219 (13)	1.5162 (13)	1.5275 (13)
P—O2	1.611 (7)	1.569 (4)	1.631 (4)
P—O2^v	1.610 (6)	1.569 (4)	1.631 (4)
P—O2'	1.5613 (11)	1.5501 (9)	1.5749 (13)
P—O2'^v	1.5613 (11)	1.5501 (9)	1.5749 (13)
P—O3	1.5159 (15)	1.5063 (15)	1.5237 (15)
P—O3^vi	1.5159 (15)	1.5063 (15)	1.5237 (15)
O2—O2'	0.298 (14)	0.228 (15)	0.335 (12)
O2—O2'^v	0.642 (14)	0.560 (17)	0.684 (12)
O2'—O2'^v	0.348 (11)	0.348 (11)	0.348 (11)
O1^i—Zn—O1^ii	80.40 (4)	79.57 (4)	81.07 (4)
O1^i—Zn—O3^iii	157.23 (10)	142.79 (12)	167.84 (11)
O1^i—Zn—O3^iv	94.16 (7)	92.23 (8)	95.42 (8)
O1^ii—Zn—O3^iii	94.14 (7)	92.14 (8)	95.42 (8)
O1^ii—Zn—O3^iv	157.27 (10)	143.18 (12)	168.14 (10)
O3^iii—Zn—O3^iv	98.37 (6)	97.53 (6)	99.75 (6)
O1—P—O2	104.3 (3)	100.8 (3)	107.7 (4)
O1—P—O2^v	104.3 (3)	100.8 (3)	107.7 (4)
O1—P—O2'	104.31 (7)	103.63 (7)	105.03 (7)
O1—P—O2'^v	104.31 (7)	103.63 (7)	105.03 (7)
O1—P—O3	112.04 (6)	111.78 (6)	112.55 (6)
O1—P—O3^vi	112.05 (6)	111.78 (6)	112.55 (6)
O2—P—O2'	10.6 (5)	8.0 (5)	11.9 (5)
O2—P—O2'^v	23.2 (5)	20.3 (6)	24.7 (4)
O2—P—O3	96.9 (4)	94.6 (5)	97.7 (4)
O2—P—O3^vi	118.6 (4)	117.5 (5)	121.5 (4)
O2^v—P—O2'	23.2 (5)	20.3 (6)	24.7 (4)
O2^v—P—O2'^v	10.6 (5)	8.0 (5)	11.9 (5)
O2^v—P—O3	118.6 (4)	117.5 (5)	121.5 (4)
O2^v—P—O3^vi	96.9 (4)	94.6 (5)	97.7 (4)
O2'—P—O2'^v	12.8 (4)	12.7 (4)	12.9 (4)
O2'—P—O3	102.4 (3)	96.6 (3)	108.3 (3)
O2'—P—O3^vi	113.5 (3)	107.7 (3)	119.3 (3)
O2'^v—P—O3	113.5 (3)	107.7 (3)	119.3 (3)
O2'^v—P—O3^vi	102.4 (3)	96.6 (3)	108.3 (3)
O3—P—O3^vi	111.90 (9)	111.52 (9)	112.28 (9)
Zn^vii—O1—Zn^viii	99.53 (8)	98.19 (9)	100.92 (8)
Zn^vii—O1—P	129.60 (5)	127.90 (4)	131.41 (4)
Zn^viii—O1—P	129.59 (5)	127.90 (4)	131.41 (4)
P—O2—P^ix	148.7 (8)	147.1 (7)	151.9 (10)
P—O2—O2'	74.5 (11)	69.1 (2)	83.6 (10)
P—O2—O2'^v	74.4 (6)	72.4 (5)	79.3 (6)
P^ix—O2—O2'	74.3 (11)	68.9 (2)	83.0 (10)
P^ix—O2—O2'^v	74.3 (6)	72.4 (5)	79.0 (6)
O2'—O2—O2'^v	6.4 (9)	0.0 (5)	17.1 (18)
P—O2'—P^ix	167.2 (6)	163.4 (6)	171.0 (6)
P—O2'—O2	95 (2)	88 (3)	103 (3)
P—O2'—O2^v	82.3 (10)	80.2 (11)	87.0 (11)
P—O2'—O2'^v	83.6 (3)	81.6 (3)	85.7 (3)
P^ix—O2'—O2	95 (2)	88 (3)	103 (3)
P^ix—O2'—O2^v	82.5 (10)	80.2 (11)	87.2 (11)
P^ix—O2'—O2'^v	83.6 (3)	81.6 (3)	85.7 (3)
O2—O2'—O2'^v	168.6 (14)	152 (2)	180.0 (5)
O2^v—O2'—O2'^v	5.1 (5)	0.0 (5)	11.1 (3)
Zn^x—O3—P	134.11 (11)	126.37 (11)	139.82 (11)

Symmetry codes: (i) x₁, x₂, x₃+1, x₄; (ii) −x₁+1, x₂, −x₃+1, −x₄+1/2; (iii) x₁−1/2, x₂+1/2, x₃, x₄; (iv) −x₁+3/2, x₂+1/2, −x₃+2, −x₄+1/2; (v) −x₁+2, −x₂, −x₃+1, −x₄; (vi) x₁, −x₂, x₃, x₄+1/2; (vii) x₁, x₂, x₃−1, x₄; (viii) −x₁+1, −x₂, −x₃+1, −x₄; (ix) −x₁+2, x₂, −x₃+1, −x₄+1/2; (x) x₁+1/2, x₂−1/2, x₃, x₄.

(alpha2_zn2p2o7_420) zinc(II) diphosphate(V)

Crystal data

O7P2Zn2	F(000) = 292
Mr = 304.7	Dx = 4.240 Mg m^−3
Monoclinic, C2/m(α0γ)0s†	Mo Kα radiation, λ = 0.71073 Å
q = 0.32940(14)a* + 0.40083(9)c*	Cell parameters from 5902 reflections
a = 6.6025 (2) Å	θ = 3.4–45.3°
b = 8.2826 (2) Å	µ = 10.70 mm^−1
c = 4.5251 (1) Å	T = 420 K
β = 105.3996 (14)°	Rod, translucent colourless
V = 238.58 (1) Å^3	0.42 × 0.30 × 0.06 mm
Z = 2

† Symmetry operations: (1) x₁, x₂, x₃, x₄; (2) −x₁, x₂, −x₃, −x₄+1/2; (3) −x₁, −x₂, −x₃, −x₄; (4) x₁, −x₂, x₃, x₄+1/2; (5) x₁+1/2, x₂+1/2, x₃, x₄; (6) −x₁+1/2, x₂+1/2, −x₃, −x₄+1/2; (7) −x₁+1/2, −x₂+1/2, −x₃, −x₄; (8) x₁+1/2, −x₂+1/2, x₃, x₄+1/2.

Data collection

Bruker KAPPA APEX II CCD diffractometer	5064 independent reflections
Radiation source: X-ray tube	2089 reflections with I > 3σ(I)
Graphite monochromator	Rint = 0.026
ω and φ scans	θmax = 45.4°, θmin = 2.1°
Absorption correction: multi-scan SADABS	h = −13→13
Tmin = 0.025, Tmax = 0.60	k = −16→16
13592 measured reflections	l = −9→5

Refinement

Refinement on F	1 constraint
R[F > 3σ(F)] = 0.025	Weighting scheme based on measured s.u.'s w = 1/(σ^2(F) + 0.0001F^2)
wR(F) = 0.041	(Δ/σ)max = 0.039
S = 1.19	Δρmax = 0.94 e Å^−3
5064 reflections	Δρmin = −0.83 e Å^−3
146 parameters	Extinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)
0 restraints	Extinction coefficient: 2380 (80)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Zn	0.5	0.18963 (2)	1	0.01887 (7)
P	0.78928 (3)	0	0.59062 (4)	0.00919 (4)
O1	0.62148 (8)	0	0.28611 (12)	0.01086 (10)
O2	1	−0.0563 (14)	0.5	0.0183 (13)	0.153 (5)
O2'	1	−0.0219 (13)	0.5	0.041 (3)	0.347 (5)
O3	0.78161 (8)	−0.15143 (5)	0.77487 (10)	0.01948 (11)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn	0.02312 (13)	0.00841 (5)	0.01745 (13)	0	−0.00798 (7)	0
P	0.00769 (6)	0.01192 (8)	0.00725 (7)	0	0.00074 (5)	0
O1	0.01088 (16)	0.01193 (18)	0.00802 (16)	0	−0.00057 (13)	0
O2	0.0053 (13)	0.025 (3)	0.0263 (18)	0	0.0071 (12)	0
O2'	0.0116 (7)	0.066 (7)	0.0486 (16)	0	0.0155 (9)	0
O3	0.0303 (2)	0.01123 (15)	0.01359 (16)	0.00608 (14)	0.00000 (15)	0.00262 (12)

Geometric parameters (Å, º)

	Average	Minimum	Maximum
Zn—O1^i	2.0602 (14)	2.0129 (15)	2.1023 (17)
Zn—O1^ii	2.0600 (14)	2.0126 (15)	2.1015 (17)
Zn—O3^iii	2.0193 (19)	1.969 (2)	2.066 (2)
Zn—O3^iv	2.0189 (19)	1.969 (2)	2.065 (2)
P—O1	1.5219 (14)	1.5197 (14)	1.5241 (14)
P—O2	1.613 (8)	1.595 (5)	1.622 (12)
P—O2^v	1.613 (8)	1.595 (5)	1.622 (12)
P—O2'	1.5624 (14)	1.5500 (12)	1.5772 (17)
P—O2'^v	1.5624 (14)	1.5500 (12)	1.5772 (17)
P—O3	1.5161 (16)	1.5058 (16)	1.5241 (16)
P—O3^vi	1.5161 (16)	1.5058 (16)	1.5241 (16)
O2—O2'	0.295 (18)	0.225 (19)	0.333 (16)
O2—O2'^v	0.651 (18)	0.56 (2)	0.696 (16)
O2'—O2'^v	0.362 (15)	0.362 (15)	0.362 (15)
O1^i—Zn—O1^ii	80.40 (4)	79.83 (4)	81.07 (4)
O1^i—Zn—O3^iii	157.23 (12)	143.42 (14)	167.70 (12)
O1^i—Zn—O3^iv	94.15 (8)	92.60 (9)	95.31 (10)
O1^ii—Zn—O3^iii	94.13 (8)	92.57 (9)	95.31 (10)
O1^ii—Zn—O3^iv	157.22 (12)	143.54 (14)	167.80 (12)
O3^iii—Zn—O3^iv	98.44 (6)	97.53 (6)	99.53 (6)
O1—P—O2	104.1 (5)	99.8 (4)	108.1 (5)
O1—P—O2^v	104.1 (5)	99.8 (4)	108.1 (5)
O1—P—O2'	104.29 (7)	103.66 (7)	104.99 (7)
O1—P—O2'^v	104.29 (7)	103.66 (7)	104.99 (7)
O1—P—O3	112.04 (7)	111.58 (7)	112.43 (7)
O1—P—O3^vi	112.04 (7)	111.58 (7)	112.43 (7)
O2—P—O2'	10.5 (6)	8.0 (7)	11.8 (6)
O2—P—O2'^v	23.6 (7)	20.5 (8)	25.2 (6)
O2—P—O3	96.6 (5)	94.6 (6)	97.8 (6)
O2—P—O3^vi	119.1 (5)	116.9 (6)	122.0 (6)
O2^v—P—O2'	23.5 (7)	20.5 (8)	25.2 (6)
O2^v—P—O2'^v	10.5 (6)	8.0 (7)	11.8 (6)
O2^v—P—O3	119.0 (5)	116.9 (6)	122.0 (6)
O2^v—P—O3^vi	96.6 (5)	94.6 (6)	97.8 (6)
O2'—P—O2'^v	13.3 (6)	13.2 (5)	13.4 (6)
O2'—P—O3	102.1 (4)	96.8 (3)	107.6 (4)
O2'—P—O3^vi	113.8 (3)	108.5 (3)	119.1 (3)
O2'^v—P—O3	113.7 (3)	108.5 (3)	119.1 (3)
O2'^v—P—O3^vi	102.2 (4)	96.8 (3)	107.6 (4)
O3—P—O3^vi	111.91 (10)	111.51 (10)	112.31 (9)
Zn^vii—O1—Zn^viii	99.54 (9)	97.95 (10)	100.83 (10)
Zn^vii—O1—P	129.61 (5)	127.99 (4)	131.16 (5)
Zn^viii—O1—P	129.59 (5)	127.99 (4)	131.16 (5)
P—O2—P^ix	148.2 (10)	146.5 (8)	151.8 (13)
P—O2—O2'	74.2 (14)	73.0 (18)	77.5 (8)
P—O2—O2'^v	74.1 (8)	73.0 (9)	76.7 (7)
P^ix—O2—O2'	74.2 (14)	73.0 (18)	77.8 (8)
P^ix—O2—O2'^v	74.2 (8)	73.0 (9)	76.9 (7)
O2'—O2—O2'^v	7.6 (13)	0.0 (5)	21 (3)
P—O2'—P^ix	166.7 (8)	163.2 (8)	170.1 (8)
P—O2'—O2	95 (3)	94 (3)	97 (3)
P—O2'—O2^v	82.3 (13)	81.5 (12)	84.5 (14)
P—O2'—O2'^v	83.3 (4)	81.5 (4)	85.2 (4)
P^ix—O2'—O2	95 (3)	94 (4)	97 (3)
P^ix—O2'—O2^v	82.3 (13)	81.5 (12)	84.4 (14)
P^ix—O2'—O2'^v	83.3 (4)	81.5 (4)	85.2 (4)
O2—O2'—O2'^v	166.7 (18)	147 (3)	180.0 (5)
O2^v—O2'—O2'^v	5.8 (6)	0.0 (5)	12.6 (5)
Zn^x—O3—P	134.07 (12)	127.00 (12)	139.13 (12)

Symmetry codes: (i) x₁, x₂, x₃+1, x₄; (ii) −x₁+1, x₂, −x₃+1, −x₄+1/2; (iii) x₁−1/2, x₂+1/2, x₃, x₄; (iv) −x₁+3/2, x₂+1/2, −x₃+2, −x₄+1/2; (v) −x₁+2, −x₂, −x₃+1, −x₄; (vi) x₁, −x₂, x₃, x₄+1/2; (vii) x₁, x₂, x₃−1, x₄; (viii) −x₁+1, −x₂, −x₃+1, −x₄; (ix) −x₁+2, x₂, −x₃+1, −x₄+1/2; (x) x₁+1/2, x₂−1/2, x₃, x₄.

(alpha2_zn2p2o7_430) zinc(II) diphosphate(V)

Crystal data

O7P2Zn2	F(000) = 292
Mr = 304.7	Dx = 4.239 Mg m^−3
Monoclinic, C2/m(α0γ)0s†	Mo Kα radiation, λ = 0.71073 Å
q = 0.32790(8)a* + 0.40041(5)c*	Cell parameters from 5548 reflections
a = 6.6018 (2) Å	θ = 3.4–45.3°
b = 8.2835 (2) Å	µ = 10.70 mm^−1
c = 4.5260 (1) Å	T = 430 K
β = 105.3906 (15)°	Rod, translucent colourless
V = 238.63 (1) Å^3	0.42 × 0.30 × 0.06 mm
Z = 2

† Symmetry operations: (1) x₁, x₂, x₃, x₄; (2) −x₁, x₂, −x₃, −x₄+1/2; (3) −x₁, −x₂, −x₃, −x₄; (4) x₁, −x₂, x₃, x₄+1/2; (5) x₁+1/2, x₂+1/2, x₃, x₄; (6) −x₁+1/2, x₂+1/2, −x₃, −x₄+1/2; (7) −x₁+1/2, −x₂+1/2, −x₃, −x₄; (8) x₁+1/2, −x₂+1/2, x₃, x₄+1/2.

Data collection

Bruker KAPPA APEX II CCD diffractometer	5061 independent reflections
Radiation source: X-ray tube	1949 reflections with I > 3σ(I)
Graphite monochromator	Rint = 0.027
ω and φ scans	θmax = 45.3°, θmin = 2.1°
Absorption correction: multi-scan SADABS	h = −13→13
Tmin = 0.025, Tmax = 0.60	k = −16→16
13656 measured reflections	l = −9→5

Refinement

Refinement on F	1 constraint
R[F > 3σ(F)] = 0.027	Weighting scheme based on measured s.u.'s w = 1/(σ^2(F) + 0.0001F^2)
wR(F) = 0.044	(Δ/σ)max = 0.043
S = 1.22	Δρmax = 0.79 e Å^−3
5061 reflections	Δρmin = −0.78 e Å^−3
146 parameters	Extinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)
0 restraints	Extinction coefficient: 2260 (90)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Zn	0.5	0.18972 (2)	1	0.01846 (8)
P	0.78924 (3)	0	0.59062 (4)	0.00869 (4)
O1	0.62139 (8)	0	0.28648 (12)	0.01024 (11)
O2	1	−0.0579 (18)	0.5	0.0140 (16)	0.105 (4)
O2'	1	−0.0244 (9)	0.5	0.038 (2)	0.395 (4)
O3	0.78147 (9)	−0.15150 (6)	0.77500 (11)	0.01886 (12)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn	0.02256 (16)	0.00800 (5)	0.01712 (16)	0	−0.00821 (8)	0
P	0.00694 (7)	0.01182 (8)	0.00663 (7)	0	0.00062 (5)	0
O1	0.00970 (17)	0.01160 (18)	0.00768 (16)	0	−0.00075 (13)	0
O2	0.0037 (17)	0.018 (4)	0.022 (2)	0	0.0051 (16)	0
O2'	0.0104 (6)	0.060 (6)	0.0482 (14)	0	0.0147 (8)	0
O3	0.0290 (2)	0.01106 (16)	0.01344 (16)	0.00644 (15)	0.00022 (15)	0.00268 (12)

Geometric parameters (Å, º)

	Average	Minimum	Maximum
Zn—O1^i	2.0613 (16)	2.0108 (18)	2.104 (2)
Zn—O1^ii	2.0615 (16)	2.0114 (18)	2.106 (2)
Zn—O3^iii	2.019 (2)	1.974 (2)	2.063 (3)
Zn—O3^iv	2.019 (2)	1.975 (2)	2.066 (3)
P—O1	1.5210 (16)	1.5103 (16)	1.5319 (16)
P—O2	1.619 (13)	1.568 (7)	1.633 (19)
P—O2^v	1.619 (13)	1.568 (7)	1.633 (19)
P—O2'	1.5649 (12)	1.5553 (11)	1.5773 (13)
P—O2'^v	1.5648 (12)	1.5553 (11)	1.5773 (13)
P—O3	1.5166 (19)	1.5068 (19)	1.5248 (19)
P—O3^vi	1.5166 (19)	1.5068 (19)	1.5248 (19)
O2—O2'	0.29 (2)	0.20 (2)	0.336 (16)
O2—O2'^v	0.69 (2)	0.58 (3)	0.741 (16)
O2'—O2'^v	0.405 (11)	0.405 (11)	0.405 (11)
O1^i—Zn—O1^ii	80.45 (5)	79.75 (5)	80.96 (5)
O1^i—Zn—O3^iii	157.21 (14)	143.74 (17)	167.56 (14)
O1^i—Zn—O3^iv	94.12 (9)	92.89 (11)	94.92 (10)
O1^ii—Zn—O3^iii	94.11 (9)	92.85 (11)	94.92 (10)
O1^ii—Zn—O3^iv	157.11 (14)	143.40 (17)	167.30 (14)
O3^iii—Zn—O3^iv	98.51 (7)	97.73 (7)	99.41 (7)
O1—P—O2	104.1 (7)	99.9 (7)	108.0 (7)
O1—P—O2^v	104.1 (7)	99.9 (7)	108.0 (7)
O1—P—O2'	104.33 (8)	104.11 (8)	104.69 (8)
O1—P—O2'^v	104.33 (8)	104.11 (8)	104.69 (8)
O1—P—O3	112.02 (8)	111.62 (8)	112.45 (8)
O1—P—O3^vi	112.03 (8)	111.62 (8)	112.45 (8)
O2—P—O2'	10.2 (7)	7.0 (8)	11.8 (6)
O2—P—O2'^v	24.8 (8)	20.9 (10)	26.7 (6)
O2—P—O3	95.5 (7)	94.3 (9)	98.1 (9)
O2—P—O3^vi	120.2 (7)	117.0 (9)	121.6 (8)
O2^v—P—O2'	24.7 (8)	20.9 (10)	26.7 (6)
O2^v—P—O2'^v	10.1 (7)	7.0 (8)	11.8 (6)
O2^v—P—O3	120.1 (7)	117.0 (9)	121.6 (8)
O2^v—P—O3^vi	95.5 (7)	94.3 (9)	98.1 (9)
O2'—P—O2'^v	14.9 (4)	14.8 (4)	14.9 (4)
O2'—P—O3	101.5 (3)	97.5 (3)	105.8 (3)
O2'—P—O3^vi	114.4 (2)	110.5 (3)	118.7 (2)
O2'^v—P—O3	114.4 (2)	110.5 (3)	118.7 (2)
O2'^v—P—O3^vi	101.5 (3)	97.5 (3)	105.8 (3)
O3—P—O3^vi	111.85 (11)	111.67 (11)	112.03 (11)
Zn^vii—O1—Zn^viii	99.50 (11)	98.10 (11)	101.17 (11)
Zn^vii—O1—P	129.61 (6)	128.44 (6)	131.03 (5)
Zn^viii—O1—P	129.60 (6)	128.44 (6)	131.03 (5)
P—O2—P^ix	146.9 (14)	144.2 (10)	152 (2)
P—O2—O2'	73 (2)	68.3 (3)	85 (2)
P—O2—O2'^v	73.4 (12)	71.6 (12)	79.0 (11)
P^ix—O2—O2'	74 (2)	68.4 (3)	85 (2)
P^ix—O2—O2'^v	73.5 (12)	71.6 (12)	79.3 (12)
O2'—O2—O2'^v	9(2)	0.1 (19)	25 (5)
P—O2'—P^ix	165.1 (5)	162.5 (5)	167.9 (5)
P—O2'—O2	96 (5)	88 (6)	105 (6)
P—O2'—O2^v	81.8 (19)	79 (2)	86 (2)
P—O2'—O2'^v	82.6 (3)	81.2 (3)	84.0 (3)
P^ix—O2'—O2	96 (5)	87 (6)	104 (6)
P^ix—O2'—O2^v	81.8 (19)	79 (2)	86 (2)
P^ix—O2'—O2'^v	82.6 (3)	81.2 (3)	84.0 (3)
O2—O2'—O2'^v	166 (3)	143 (5)	180 (4)
O2^v—O2'—O2'^v	5.5 (9)	0.0 (5)	12.1 (6)
Zn^x—O3—P	133.91 (14)	126.64 (15)	138.26 (14)

Symmetry codes: (i) x₁, x₂, x₃+1, x₄; (ii) −x₁+1, x₂, −x₃+1, −x₄+1/2; (iii) x₁−1/2, x₂+1/2, x₃, x₄; (iv) −x₁+3/2, x₂+1/2, −x₃+2, −x₄+1/2; (v) −x₁+2, −x₂, −x₃+1, −x₄; (vi) x₁, −x₂, x₃, x₄+1/2; (vii) x₁, x₂, x₃−1, x₄; (viii) −x₁+1, −x₂, −x₃+1, −x₄; (ix) −x₁+2, x₂, −x₃+1, −x₄+1/2; (x) x₁+1/2, x₂−1/2, x₃, x₄.

(alpha2_zn2p2o7_450) zinc(II) diphosphate(V)

Crystal data

O7P2Zn2	F(000) = 292
Mr = 304.7	Dx = 4.239 Mg m^−3
Monoclinic, C2/m(α0γ)0s†	Mo Kα radiation, λ = 0.71073 Å
q = 0.3268(3)a* + 0.3989(2)c*	Cell parameters from 4377 reflections
a = 6.6011 (2) Å	θ = 4.0–45.3°
b = 8.2839 (3) Å	µ = 10.7 mm^−1
c = 4.5266 (2) Å	T = 450 K
β = 105.3869 (17)°	Rod, translucent colourless
V = 238.66 (2) Å^3	0.42 × 0.30 × 0.06 mm
Z = 2

† Symmetry operations: (1) x₁, x₂, x₃, x₄; (2) −x₁, x₂, −x₃, −x₄+1/2; (3) −x₁, −x₂, −x₃, −x₄; (4) x₁, −x₂, x₃, x₄+1/2; (5) x₁+1/2, x₂+1/2, x₃, x₄; (6) −x₁+1/2, x₂+1/2, −x₃, −x₄+1/2; (7) −x₁+1/2, −x₂+1/2, −x₃, −x₄; (8) x₁+1/2, −x₂+1/2, x₃, x₄+1/2.

Data collection

Bruker KAPPA APEX II CCD diffractometer	5061 independent reflections
Radiation source: X-ray tube	1643 reflections with I > 3σ(I)
Graphite monochromator	Rint = 0.026
ω and φ scans	θmax = 45.4°, θmin = 2.1°
Absorption correction: multi-scan SADABS	h = −13→13
Tmin = 0.025, Tmax = 0.60	k = −16→16
13609 measured reflections	l = −9→5

Refinement

Refinement on F	1 constraint
R[F > 3σ(F)] = 0.029	Weighting scheme based on measured s.u.'s w = 1/(σ^2(F) + 0.0001F^2)
wR(F) = 0.048	(Δ/σ)max = 0.041
S = 1.22	Δρmax = 0.81 e Å^−3
5061 reflections	Δρmin = −0.82 e Å^−3
143 parameters	Extinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)
0 restraints	Extinction coefficient: 2610 (90)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Zn	0.5	0.18982 (3)	1	0.02042 (11)
P	0.78911 (3)	0	0.59073 (4)	0.00965 (5)
O1	0.62120 (8)	0	0.28642 (13)	0.01136 (11)
O2	1	−0.068 (3)	0.5	0.009 (2)	0.050 (3)
O2'	1	−0.0281 (6)	0.5	0.0337 (17)	0.450 (3)
O3	0.78150 (10)	−0.15154 (6)	0.77508 (12)	0.02031 (14)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn	0.02518 (18)	0.00904 (5)	0.0185 (3)	0	−0.00906 (10)	0
P	0.00785 (7)	0.01289 (8)	0.00750 (7)	0	0.00081 (5)	0
O1	0.01101 (17)	0.01278 (19)	0.00846 (17)	0	−0.00059 (13)	0
O2	0.001 (2)	0.004 (5)	0.023 (4)	0	0.004 (2)	0
O2'	0.0116 (5)	0.046 (5)	0.0470 (12)	0	0.0141 (6)	0
O3	0.0309 (3)	0.01222 (17)	0.01455 (18)	0.00677 (16)	0.00043 (18)	0.00303 (13)

Geometric parameters (Å, º)

	Average	Minimum	Maximum
Zn—O1^i	2.061 (2)	2.007 (3)	2.110 (3)
Zn—O1^ii	2.061 (2)	2.009 (3)	2.114 (3)
Zn—O3^iii	2.017 (3)	1.993 (3)	2.040 (2)
Zn—O3^iv	2.017 (3)	1.993 (3)	2.040 (2)
P—O1	1.522 (2)	1.519 (2)	1.524 (2)
P—O2	1.646 (7)	1.641 (7)	1.653 (7)
P—O2^v	1.646 (7)	1.641 (7)	1.653 (7)
P—O2'	1.5699 (12)	1.5626 (11)	1.5791 (12)
P—O2'^v	1.5699 (12)	1.5626 (11)	1.5791 (12)
P—O3	1.516 (3)	1.508 (3)	1.527 (3)
P—O3^vi	1.516 (3)	1.508 (3)	1.527 (3)
O2—O2'	0.33 (2)	0.33 (2)	0.33 (2)
O2—O2'^v	0.79 (2)	0.79 (2)	0.79 (2)
O2'—O2'^v	0.465 (7)	0.465 (7)	0.465 (7)
O1^i—Zn—O1^ii	80.43 (7)	80.20 (7)	80.79 (7)
O1^i—Zn—O3^iii	157.2 (2)	148.3 (3)	165.8 (2)
O1^i—Zn—O3^iv	94.18 (14)	92.18 (16)	94.82 (14)
O1^ii—Zn—O3^iii	94.15 (14)	92.07 (16)	94.82 (14)
O1^ii—Zn—O3^iv	157.1 (2)	147.7 (3)	165.4 (2)
O3^iii—Zn—O3^iv	98.59 (10)	97.48 (10)	99.24 (10)
O1—P—O2	103.79 (12)	103.54 (12)	104.09 (12)
O1—P—O2^v	103.79 (12)	103.54 (12)	104.09 (12)
O1—P—O2'	104.27 (11)	103.83 (12)	104.68 (12)
O1—P—O2'^v	104.27 (11)	103.83 (12)	104.68 (12)
O1—P—O3	112.07 (11)	111.64 (11)	112.61 (11)
O1—P—O3^vi	112.07 (11)	111.64 (11)	112.61 (11)
O2—P—O2'	11.4 (7)	11.4 (7)	11.5 (7)
O2—P—O2'^v	28.5 (7)	28.4 (7)	28.6 (7)
O2—P—O3	92.0 (6)	89.2 (6)	94.0 (6)
O2—P—O3^vi	123.4 (6)	122.5 (6)	124.0 (6)
O2^v—P—O2'	28.5 (7)	28.4 (7)	28.6 (7)
O2^v—P—O2'^v	11.4 (7)	11.4 (7)	11.5 (7)
O2^v—P—O3	123.4 (6)	122.5 (6)	124.0 (6)
O2^v—P—O3^vi	92.0 (6)	89.2 (6)	94.0 (6)
O2'—P—O2'^v	17.0 (2)	17.0 (2)	17.1 (2)
O2'—P—O3	100.50 (19)	97.93 (19)	104.15 (19)
O2'—P—O3^vi	115.33 (19)	112.78 (19)	118.94 (18)
O2'^v—P—O3	115.32 (19)	112.78 (19)	118.94 (18)
O2'^v—P—O3^vi	100.51 (19)	97.93 (19)	104.15 (19)
O3—P—O3^vi	111.86 (16)	110.54 (16)	113.14 (16)
Zn^vii—O1—Zn^viii	99.54 (17)	97.78 (17)	101.16 (17)
Zn^vii—O1—P	129.60 (8)	128.56 (10)	130.43 (10)
Zn^viii—O1—P	129.59 (8)	128.56 (10)	130.43 (10)
P—O2—P^ix	141.2 (14)	140.2 (14)	141.8 (14)
P—O2—O2'	70.6 (7)	69.8 (7)	71.0 (7)
P—O2—O2'^v	70.6 (7)	69.8 (7)	71.0 (7)
P^ix—O2—O2'	70.6 (7)	69.8 (7)	71.0 (7)
P^ix—O2—O2'^v	70.6 (7)	69.8 (7)	71.0 (7)
O2'—O2—O2'^v	0.0 (5)	0.0 (5)	0.0 (5)
P—O2'—P^ix	163.0 (3)	161.2 (3)	164.7 (3)
P—O2'—O2	97.96 (17)	97.55 (17)	98.85 (17)
P—O2'—O2^v	80.92 (17)	80.55 (17)	81.79 (17)
P—O2'—O2'^v	81.47 (17)	80.55 (17)	82.45 (17)
P^ix—O2'—O2	97.95 (17)	97.55 (17)	98.83 (17)
P^ix—O2'—O2^v	80.93 (17)	80.55 (17)	81.78 (17)
P^ix—O2'—O2'^v	81.48 (17)	80.55 (17)	82.45 (17)
O2—O2'—O2'^v	180.0 (5)	180.0 (5)	180.0 (5)
O2^v—O2'—O2'^v	0.0 (5)	0.0 (5)	0.0 (5)
Zn^x—O3—P	133.98 (19)	129.14 (17)	138.8 (2)

Symmetry codes: (i) x₁, x₂, x₃+1, x₄; (ii) −x₁+1, x₂, −x₃+1, −x₄+1/2; (iii) x₁−1/2, x₂+1/2, x₃, x₄; (iv) −x₁+3/2, x₂+1/2, −x₃+2, −x₄+1/2; (v) −x₁+2, −x₂, −x₃+1, −x₄; (vi) x₁, −x₂, x₃, x₄+1/2; (vii) x₁, x₂, x₃−1, x₄; (viii) −x₁+1, −x₂, −x₃+1, −x₄; (ix) −x₁+2, x₂, −x₃+1, −x₄+1/2; (x) x₁+1/2, x₂−1/2, x₃, x₄.

(alpha2_zn2p2o7_500) zinc(II) diphosphate(V)

Crystal data

O7P2Zn2	F(000) = 292
Mr = 304.7	Dx = 4.235 Mg m^−3
Monoclinic, C2/m(α0γ)0s†	Mo Kα radiation, λ = 0.71073 Å
q = 0.3239(14)a* + 0.3966(9)c*	Cell parameters from 3836 reflections
a = 6.5998 (4) Å	θ = 4.0–45.3°
b = 8.2845 (5) Å	µ = 10.69 mm^−1
c = 4.5300 (3) Å	T = 500 K
β = 105.335 (3)°	Rod, translucent colourless
V = 238.86 (3) Å^3	0.42 × 0.30 × 0.06 mm
Z = 2

† Symmetry operations: (1) x₁, x₂, x₃, x₄; (2) −x₁, x₂, −x₃, −x₄+1/2; (3) −x₁, −x₂, −x₃, −x₄; (4) x₁, −x₂, x₃, x₄+1/2; (5) x₁+1/2, x₂+1/2, x₃, x₄; (6) −x₁+1/2, x₂+1/2, −x₃, −x₄+1/2; (7) −x₁+1/2, −x₂+1/2, −x₃, −x₄; (8) x₁+1/2, −x₂+1/2, x₃, x₄+1/2.

Data collection

Bruker KAPPA APEX II CCD diffractometer	2969 independent reflections
Radiation source: X-ray tube	1331 reflections with I > 3σ(I)
Graphite monochromator	Rint = 0.025
ω and φ scans	θmax = 45.4°, θmin = 3.5°
Absorption correction: multi-scan SADABS	h = −13→12
Tmin = 0.025, Tmax = 0.60	k = −16→16
8052 measured reflections	l = −5→9

Refinement

Refinement on F	1 constraint
R[F > 3σ(F)] = 0.030	Weighting scheme based on measured s.u.'s w = 1/(σ^2(F) + 0.0001F^2)
wR(F) = 0.047	(Δ/σ)max = 0.020
S = 1.50	Δρmax = 1.04 e Å^−3
2969 reflections	Δρmin = −1.13 e Å^−3
98 parameters	Extinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)
0 restraints	Extinction coefficient: 2750 (110)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Zn	0.5	0.18988 (3)	1	0.02339 (5)
P	0.78921 (3)	0	0.59064 (5)	0.01022 (6)
O1	0.62136 (11)	0	0.28655 (16)	0.01244 (14)
O2	1	−0.072 (5)	0.5	0.013 (6)	0.027 (4)
O2'	1	−0.0304 (7)	0.5	0.037 (2)	0.473 (4)
O3	0.78098 (12)	−0.15170 (8)	0.77509 (15)	0.02105 (15)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn	0.02790 (9)	0.00998 (6)	0.02228 (9)	0	−0.01094 (6)	0
P	0.00840 (8)	0.01341 (10)	0.00826 (9)	0	0.00114 (6)	0
O1	0.0124 (2)	0.0138 (2)	0.0092 (2)	0	−0.00059 (17)	0
O2	0.007 (7)	0.002 (8)	0.024 (11)	0	−0.008 (7)	0
O2'	0.0111 (6)	0.056 (6)	0.0486 (14)	0	0.0155 (8)	0
O3	0.0313 (3)	0.0131 (2)	0.0157 (2)	0.00649 (19)	0.0007 (2)	0.00333 (17)

Geometric parameters (Å, º)

	Average	Minimum	Maximum
Zn—O1^i	2.0619 (11)	2.0542 (11)	2.0692 (11)
Zn—O1^ii	2.0618 (11)	2.0542 (11)	2.0692 (11)
Zn—O3^iii	2.0178 (12)	2.0087 (12)	2.0265 (12)
Zn—O3^iv	2.0176 (12)	2.0080 (12)	2.0265 (12)
P—O1	1.5224 (7)	1.5223 (7)	1.5224 (7)
P—O2	1.659 (15)	1.657 (15)	1.663 (15)
P—O2^v	1.659 (15)	1.657 (15)	1.663 (15)
P—O2'	1.5716 (10)	1.5692 (10)	1.5740 (11)
P—O2'^v	1.5715 (10)	1.5692 (10)	1.5740 (11)
P—O3	1.5182 (13)	1.5158 (13)	1.5204 (13)
P—O3^vi	1.5182 (13)	1.5158 (13)	1.5204 (13)
O2—O2'	0.34 (4)	0.34 (4)	0.34 (4)
O2—O2'^v	0.85 (4)	0.85 (4)	0.85 (4)
O2'—O2'^v	0.504 (8)	0.504 (8)	0.504 (8)
O1^i—Zn—O1^ii	80.55 (4)	80.30 (4)	80.80 (4)
O1^i—Zn—O3^iii	157.11 (5)	156.01 (6)	157.89 (6)
O1^i—Zn—O3^iv	94.09 (4)	93.67 (4)	94.45 (4)
O1^ii—Zn—O3^iii	94.08 (4)	93.64 (4)	94.45 (4)
O1^ii—Zn—O3^iv	157.13 (5)	156.06 (6)	157.93 (6)
O3^iii—Zn—O3^iv	98.84 (5)	98.58 (5)	99.11 (5)
O1—P—O2	103.61 (12)	103.42 (13)	103.70 (12)
O1—P—O2^v	103.61 (12)	103.42 (13)	103.70 (12)
O1—P—O2'	104.25 (4)	104.13 (4)	104.36 (3)
O1—P—O2'^v	104.25 (4)	104.13 (4)	104.36 (3)
O1—P—O3	112.00 (6)	111.95 (6)	112.05 (6)
O1—P—O3^vi	112.00 (6)	111.95 (6)	112.05 (6)
O2—P—O2'	11.8 (14)	11.8 (14)	11.9 (14)
O2—P—O2'^v	30.3 (14)	30.2 (14)	30.3 (14)
O2—P—O3	90.5 (12)	89.6 (12)	91.0 (12)
O2—P—O3^vi	125.1 (11)	124.6 (11)	126.0 (11)
O2^v—P—O2'	30.3 (14)	30.2 (14)	30.3 (14)
O2^v—P—O2'^v	11.8 (14)	11.8 (14)	11.9 (14)
O2^v—P—O3	125.1 (11)	124.6 (11)	126.0 (11)
O2^v—P—O3^vi	90.5 (12)	89.6 (12)	91.0 (12)
O2'—P—O2'^v	18.4 (3)	18.4 (3)	18.4 (3)
O2'—P—O3	100.02 (19)	98.56 (19)	101.49 (19)
O2'—P—O3^vi	116.07 (19)	114.62 (19)	117.53 (19)
O2'^v—P—O3	116.07 (19)	114.62 (19)	117.53 (19)
O2'^v—P—O3^vi	100.03 (19)	98.56 (19)	101.49 (19)
O3—P—O3^vi	111.77 (7)	111.76 (7)	111.77 (7)
Zn^vii—O1—Zn^viii	99.45 (3)	99.43 (3)	99.46 (3)
Zn^vii—O1—P	129.66 (7)	129.08 (7)	130.25 (7)
Zn^viii—O1—P	129.66 (7)	129.08 (7)	130.25 (7)
P—O2—P^ix	139 (3)	138 (3)	139 (3)
P—O2—O2'	69.3 (14)	68.8 (14)	69.5 (14)
P—O2—O2'^v	69.3 (14)	68.8 (14)	69.5 (14)
P^ix—O2—O2'	69.3 (14)	68.8 (14)	69.5 (14)
P^ix—O2—O2'^v	69.3 (14)	68.8 (14)	69.5 (14)
O2'—O2—O2'^v	0.0 (5)	0.0 (5)	0.0 (5)
P—O2'—P^ix	161.6 (4)	160.5 (4)	162.6 (4)
P—O2'—O2	98.9 (2)	98.7 (2)	99.4 (2)
P—O2'—O2^v	80.5 (2)	80.2 (2)	80.9 (2)
P—O2'—O2'^v	80.8 (2)	80.2 (2)	81.3 (2)
P^ix—O2'—O2	98.9 (2)	98.7 (2)	99.4 (2)
P^ix—O2'—O2^v	80.5 (2)	80.2 (2)	81.0 (2)
P^ix—O2'—O2'^v	80.8 (2)	80.2 (2)	81.3 (2)
O2—O2'—O2'^v	180.0 (5)	180.0 (5)	180.0 (5)
O2^v—O2'—O2'^v	0.0 (5)	0.0 (5)	0.0 (5)
Zn^x—O3—P	133.74 (8)	132.27 (8)	135.25 (8)

Symmetry codes: (i) x₁, x₂, x₃+1, x₄; (ii) −x₁+1, x₂, −x₃+1, −x₄+1/2; (iii) x₁−1/2, x₂+1/2, x₃, x₄; (iv) −x₁+3/2, x₂+1/2, −x₃+2, −x₄+1/2; (v) −x₁+2, −x₂, −x₃+1, −x₄; (vi) x₁, −x₂, x₃, x₄+1/2; (vii) x₁, x₂, x₃−1, x₄; (viii) −x₁+1, −x₂, −x₃+1, −x₄; (ix) −x₁+2, x₂, −x₃+1, −x₄+1/2; (x) x₁+1/2, x₂−1/2, x₃, x₄.