Bonding effects and the crystal structures of (NH₄)₂[Cu(H₂O)₆](SO₄)₂ and its H₂¹⁸O substituted form at 9.5 K

The crystal structures of the Tutton salts (NH₄)₂-[Cu(H₂O)₆](SO₄)₂, diammonium hexaaquacopper disulfate, formed with normal water and isotopically substituted H₂¹⁸O, have been determined by X-ray diffraction at 9.5 K and are very similar, with Cu-O(7) the longest of the Cu-O bonds of the Jahn-Teller distorted octahedral [Cu(H₂O)₆]²⁺ complex. It is known that structural differences accompany deuteration of (NH₄)₂[Cu(H₂O)₆](SO₄)₂, the most dramatic of which is a switch to Cu-O(8) as the longest such bond. The present result suggests that the structural differences are associated with hydrogen-bonding effects rather than with increased mass of the water ligands affecting the Jahn-Teller coupling. The Jahn-Teller distortions and hydrogen-bonding contacts in the compounds are compared with those reported for other Tutton salts at ambient and high pressure.

Computing details

For both compounds, data collection: Local diffractometer control software; cell refinement: Local diffractometer control software; data reduction: PROFIT (Streltsov & Zavodnik, 1989); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Sheldrick, 1983); software used to prepare material for publication: SHELXTL (Sheldrick, 1983).

Figures

Fig. 1.

(sn)

Crystal data

(NH4)2[Cu(H2O)6](SO4)2	F(000) = 414
Mr = 399.84	Dx = 1.961 Mg m^−3
Monoclinic, P21/a	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yab	Cell parameters from 12 reflections
a = 9.0964 (9) Å	θ = 20.8–23.4°
b = 12.2225 (11) Å	µ = 1.99 mm^−1
c = 6.3447 (7) Å	T = 10 K
β = 106.295 (7)°	Plate, lightblue
V = 677.07 (12) Å^3	0.57 × 0.50 × 0.20 mm
Z = 2

Data collection

Huber 512 diffractometer	1930 reflections with I > 2σ(I)
Radiation source: normal-focus sealed tube	Rint = 0.039
None monochromator	θmax = 30.1°, θmin = 2.9°
ω/2θ scans	h = −12→12
Absorption correction: gaussian ?	k = −17→17
Tmin = 0.336, Tmax = 0.713	l = 0→8
4295 measured reflections	3 standard reflections every 100 reflections
1988 independent reflections	intensity decay: 0.5%

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.021	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.060	w = 1/[σ^2(Fo^2) + (0.031P)^2 + 0.228P] where P = (Fo^2 + 2Fc^2)/3
S = 1.12	(Δ/σ)max < 0.001
1988 reflections	Δρmax = 0.65 e Å^−3
129 parameters	Δρmin = −0.67 e Å^−3
0 restraints	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0162 (18)

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

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

	x	y	z	Uiso*/Ueq
Cu	0.0000	0.0000	0.0000	0.00280 (8)
S1	0.41985 (3)	0.13459 (2)	0.74317 (4)	0.00309 (8)
O3	0.42991 (9)	0.22753 (7)	0.59587 (14)	0.00541 (15)
O4	0.55809 (9)	0.06696 (7)	0.78323 (14)	0.00638 (16)
O5	0.28391 (9)	0.06777 (6)	0.63161 (13)	0.00535 (16)
O6	0.40174 (9)	0.17903 (7)	0.95209 (14)	0.00577 (15)
O7	0.18660 (10)	0.11856 (7)	0.17780 (15)	0.00650 (16)
O8	−0.15738 (9)	0.10924 (7)	0.02938 (14)	0.00562 (16)
O9	−0.00600 (9)	−0.06422 (7)	0.28289 (14)	0.00563 (15)
N1	0.14204 (11)	0.34170 (8)	0.35777 (17)	0.00646 (18)
H11	0.085 (2)	0.3280 (17)	0.227 (4)	0.011 (4)*
H12	0.221 (2)	0.3020 (19)	0.391 (4)	0.018 (5)*
H13	0.087 (2)	0.3260 (19)	0.443 (4)	0.018 (5)*
H14	0.167 (3)	0.414 (2)	0.377 (4)	0.024 (5)*
H15	0.220 (2)	0.0935 (19)	0.305 (4)	0.019 (5)*
H16	0.244 (3)	0.1235 (19)	0.118 (4)	0.023 (6)*
H17	−0.239 (3)	0.095 (2)	−0.051 (4)	0.024 (5)*
H18	−0.136 (2)	0.1668 (19)	0.003 (4)	0.016 (5)*
H19	−0.084 (3)	−0.055 (2)	0.309 (4)	0.024 (5)*
H20	0.018 (3)	−0.128 (2)	0.313 (4)	0.023 (5)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cu	0.00378 (11)	0.00131 (11)	0.00427 (11)	0.00049 (5)	0.00270 (7)	0.00056 (6)
S1	0.00381 (13)	0.00137 (12)	0.00480 (13)	−0.00014 (8)	0.00237 (9)	−0.00018 (8)
O3	0.0079 (3)	0.0024 (3)	0.0069 (3)	−0.0004 (3)	0.0037 (3)	0.0015 (3)
O4	0.0049 (3)	0.0045 (3)	0.0099 (3)	0.0017 (3)	0.0025 (3)	0.0001 (3)
O5	0.0051 (3)	0.0037 (3)	0.0074 (3)	−0.0020 (3)	0.0022 (3)	−0.0014 (3)
O6	0.0088 (3)	0.0043 (3)	0.0053 (3)	−0.0001 (3)	0.0038 (3)	−0.0009 (3)
O7	0.0069 (3)	0.0068 (3)	0.0066 (4)	−0.0010 (3)	0.0034 (3)	0.0001 (3)
O8	0.0052 (3)	0.0028 (3)	0.0094 (4)	0.0005 (3)	0.0029 (3)	0.0003 (3)
O9	0.0070 (3)	0.0039 (3)	0.0077 (3)	0.0012 (3)	0.0048 (3)	0.0012 (3)
N1	0.0076 (4)	0.0047 (4)	0.0083 (4)	0.0001 (3)	0.0042 (3)	0.0001 (3)

Geometric parameters (Å, º)

Cu—O9^i	1.9737 (9)	O7—H15	0.83 (2)
Cu—O9	1.9737 (9)	O7—H16	0.73 (3)
Cu—O8^i	2.0042 (8)	O8—H17	0.79 (2)
Cu—O8	2.0042 (8)	O8—H18	0.76 (2)
Cu—O7	2.2758 (9)	O9—H19	0.78 (3)
Cu—O7^i	2.2758 (9)	O9—H20	0.81 (2)
S1—O4	1.4662 (8)	N1—H11	0.87 (2)
S1—O6	1.4839 (8)	N1—H12	0.84 (2)
S1—O5	1.4853 (8)	N1—H13	0.85 (2)
S1—O3	1.4900 (8)	N1—H14	0.91 (2)
O9^i—Cu—O9	180.00 (5)	O4—S1—O3	109.75 (5)
O9^i—Cu—O8^i	88.72 (4)	O6—S1—O3	108.85 (5)
O9—Cu—O8^i	91.28 (4)	O5—S1—O3	108.05 (5)
O9^i—Cu—O8	91.28 (4)	Cu—O7—H15	105.2 (15)
O9—Cu—O8	88.72 (4)	Cu—O7—H16	109.8 (18)
O8^i—Cu—O8	180.00 (6)	H15—O7—H16	114 (2)
O9^i—Cu—O7	89.45 (3)	Cu—O8—H17	111.0 (18)
O9—Cu—O7	90.55 (3)	Cu—O8—H18	111.2 (16)
O8^i—Cu—O7	91.00 (3)	H17—O8—H18	108 (2)
O8—Cu—O7	89.00 (3)	Cu—O9—H19	113.2 (18)
O9^i—Cu—O7^i	90.55 (3)	Cu—O9—H20	121.2 (17)
O9—Cu—O7^i	89.45 (3)	H19—O9—H20	107 (2)
O8^i—Cu—O7^i	89.00 (3)	H11—N1—H12	112 (2)
O8—Cu—O7^i	91.00 (3)	H11—N1—H13	105.5 (18)
O7—Cu—O7^i	180.00 (6)	H12—N1—H13	109 (2)
O4—S1—O6	110.87 (5)	H11—N1—H14	112 (2)
O4—S1—O5	109.36 (5)	H12—N1—H14	111 (2)
O6—S1—O5	109.92 (5)	H13—N1—H14	107 (2)

Symmetry code: (i) −x, −y, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H11···O6^ii	0.87 (2)	2.05 (2)	2.8827 (13)	162 (2)
N1—H12···O3	0.84 (2)	2.18 (2)	2.9776 (13)	158 (2)
N1—H13···O3^iii	0.85 (2)	2.05 (2)	2.8909 (13)	169 (2)
N1—H14···O5^iv	0.91 (2)	1.94 (2)	2.8403 (13)	171 (2)
O7—H15···O5	0.83 (2)	2.02 (2)	2.8336 (13)	166 (2)
O7—H16···O6^v	0.73 (3)	2.12 (3)	2.8283 (12)	166 (2)
O8—H17···O4^vi	0.79 (2)	1.88 (2)	2.6715 (12)	174 (2)
O8—H18···O6^ii	0.76 (2)	1.96 (2)	2.7156 (12)	173 (2)
O9—H19···O5^vii	0.78 (3)	1.97 (3)	2.7307 (11)	167 (2)
O9—H20···O3^viii	0.81 (2)	1.88 (3)	2.6928 (12)	175 (2)

Symmetry codes: (ii) x−1/2, −y+1/2, z−1; (iii) x−1/2, −y+1/2, z; (iv) −x+1/2, y+1/2, −z+1; (v) x, y, z−1; (vi) x−1, y, z−1; (vii) −x, −y, −z+1; (viii) −x+1/2, y−1/2, −z+1.

(so)

Crystal data

(NH4)2[Cu(H2^18O)6](SO4)2	F(000) = 414
Mr = 411.84	Dx = 2.022 Mg m^−3
Monoclinic, P21/a	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac	Cell parameters from 12 reflections
a = 9.0921 (6) Å	θ = 20.8–23.4°
b = 12.2195 (8) Å	µ = 2.00 mm^−1
c = 6.3442 (5) Å	T = 10 K
β = 106.277 (5)°	Prism, lightblue
V = 676.59 (8) Å^3	0.70 × 0.53 × 0.40 mm
Z = 2

Data collection

Huber 512 diffractometer	1949 reflections with I > 2σ(I)
Radiation source: normal-focus sealed tube	Rint = 0.013
None monochromator	θmax = 30.1°, θmin = 2.9°
ω/2θ scans	h = 0→12
Absorption correction: gaussian ?	k = −17→17
Tmin = 0.405, Tmax = 0.517	l = −8→8
4102 measured reflections	3 standard reflections every 100 reflections
1986 independent reflections	intensity decay: 0.5%

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.020	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.054	w = 1/[σ^2(Fo^2) + (0.0285P)^2 + 0.388P] where P = (Fo^2 + 2Fc^2)/3
S = 1.18	(Δ/σ)max < 0.001
1986 reflections	Δρmax = 0.49 e Å^−3
129 parameters	Δρmin = −0.46 e Å^−3
0 restraints	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.050 (2)

Special details

Experimental. Prepared from 18-O enriched water.

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

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

	x	y	z	Uiso*/Ueq
Cu	0.0000	0.0000	0.0000	0.00300 (8)
S1	0.41999 (3)	0.13461 (2)	0.74317 (4)	0.00333 (8)
O3	0.43010 (9)	0.22763 (7)	0.59597 (13)	0.00560 (15)
O4	0.55825 (9)	0.06705 (7)	0.78309 (14)	0.00667 (16)
O5	0.28403 (9)	0.06783 (6)	0.63190 (13)	0.00544 (16)
O6	0.40192 (9)	0.17916 (7)	0.95197 (13)	0.00589 (15)
O7	0.18678 (10)	0.11864 (7)	0.17781 (15)	0.00661 (16)
O8	−0.15725 (10)	0.10919 (7)	0.02927 (14)	0.00568 (16)
O9	−0.00620 (10)	−0.06428 (7)	0.28256 (14)	0.00572 (15)
N1	0.14189 (12)	0.34172 (8)	0.35758 (17)	0.00676 (18)
H11	0.088 (2)	0.3284 (17)	0.221 (3)	0.014 (4)*
H12	0.215 (3)	0.2988 (19)	0.385 (3)	0.021 (5)*
H13	0.081 (2)	0.3250 (18)	0.443 (3)	0.018 (5)*
H14	0.162 (3)	0.414 (2)	0.367 (4)	0.026 (5)*
H15	0.219 (2)	0.0963 (18)	0.299 (4)	0.019 (5)*
H16	0.248 (2)	0.1212 (17)	0.124 (4)	0.016 (5)*
H17	−0.238 (3)	0.0957 (19)	−0.047 (4)	0.020 (5)*
H18	−0.139 (2)	0.1732 (19)	0.005 (3)	0.017 (5)*
H19	−0.087 (3)	−0.057 (2)	0.313 (4)	0.029 (6)*
H20	0.012 (3)	−0.1308 (19)	0.301 (4)	0.023 (5)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cu	0.00314 (11)	0.00297 (11)	0.00320 (11)	0.00050 (5)	0.00140 (7)	0.00052 (5)
S1	0.00326 (12)	0.00311 (12)	0.00373 (13)	−0.00005 (8)	0.00116 (9)	−0.00011 (8)
O3	0.0073 (3)	0.0042 (3)	0.0056 (3)	−0.0006 (3)	0.0024 (3)	0.0015 (3)
O4	0.0044 (3)	0.0064 (4)	0.0089 (4)	0.0017 (3)	0.0014 (3)	0.0000 (3)
O5	0.0043 (3)	0.0054 (4)	0.0063 (4)	−0.0017 (3)	0.0009 (3)	−0.0009 (3)
O6	0.0080 (4)	0.0061 (3)	0.0041 (3)	−0.0001 (3)	0.0026 (3)	−0.0011 (3)
O7	0.0061 (4)	0.0082 (4)	0.0057 (4)	−0.0006 (3)	0.0020 (3)	0.0005 (3)
O8	0.0043 (3)	0.0046 (4)	0.0081 (4)	0.0004 (3)	0.0017 (3)	0.0001 (3)
O9	0.0064 (4)	0.0055 (4)	0.0063 (3)	0.0014 (3)	0.0035 (3)	0.0015 (3)
N1	0.0069 (4)	0.0060 (4)	0.0078 (4)	−0.0001 (3)	0.0026 (3)	−0.0001 (3)

Geometric parameters (Å, º)

Cu—O9	1.9724 (8)	O7—H15	0.79 (2)
Cu—O9^i	1.9724 (8)	O7—H16	0.73 (2)
Cu—O8	2.0019 (8)	O8—H17	0.78 (2)
Cu—O8^i	2.0019 (8)	O8—H18	0.82 (2)
Cu—O7^i	2.2769 (9)	O9—H19	0.82 (3)
Cu—O7	2.2769 (9)	O9—H20	0.83 (2)
S1—O4	1.4655 (8)	N1—H11	0.89 (2)
S1—O6	1.4832 (8)	N1—H12	0.82 (2)
S1—O5	1.4843 (8)	N1—H13	0.90 (2)
S1—O3	1.4902 (8)	N1—H14	0.90 (3)
O9—Cu—O9^i	180.00 (7)	O4—S1—O3	109.72 (5)
O9—Cu—O8	88.74 (3)	O6—S1—O3	108.75 (5)
O9^i—Cu—O8	91.26 (3)	O5—S1—O3	108.10 (5)
O9—Cu—O8^i	91.26 (3)	Cu—O7—H15	106.5 (16)
O9^i—Cu—O8^i	88.74 (3)	Cu—O7—H16	110.8 (17)
O8—Cu—O8^i	180.00 (5)	H15—O7—H16	110 (2)
O9—Cu—O7^i	89.39 (3)	Cu—O8—H17	112.2 (17)
O9^i—Cu—O7^i	90.61 (3)	Cu—O8—H18	115.3 (15)
O8—Cu—O7^i	91.00 (3)	H17—O8—H18	107 (2)
O8^i—Cu—O7^i	89.00 (3)	Cu—O9—H19	115.4 (17)
O9—Cu—O7	90.61 (3)	Cu—O9—H20	117.6 (16)
O9^i—Cu—O7	89.39 (3)	H19—O9—H20	104 (2)
O8—Cu—O7	89.00 (3)	H11—N1—H12	106.2 (19)
O8^i—Cu—O7	91.00 (3)	H11—N1—H13	106.6 (18)
O7^i—Cu—O7	180.00 (6)	H12—N1—H13	109 (2)
O4—S1—O6	110.90 (5)	H11—N1—H14	107.0 (19)
O4—S1—O5	109.40 (5)	H12—N1—H14	118 (2)
O6—S1—O5	109.91 (5)	H13—N1—H14	109 (2)

Symmetry code: (i) −x, −y, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H11···O6^ii	0.89 (2)	2.04 (2)	2.8810 (13)	158 (2)
N1—H12···O3	0.82 (2)	2.22 (2)	2.9792 (13)	154 (2)
N1—H13···O3^iii	0.90 (2)	2.00 (2)	2.8890 (13)	171 (2)
N1—H14···O5^iv	0.90 (3)	1.94 (3)	2.8402 (13)	175 (2)
O7—H15···O5	0.79 (2)	2.06 (2)	2.8353 (12)	168 (2)
O7—H16···O6^v	0.73 (2)	2.12 (2)	2.8279 (12)	162 (2)
O8—H17···O4^vi	0.78 (2)	1.90 (2)	2.6704 (12)	176 (2)
O8—H18···O6^ii	0.82 (2)	1.89 (2)	2.7141 (12)	179 (2)
O9—H19···O5^vii	0.82 (3)	1.92 (3)	2.7287 (12)	169 (2)
O9—H20···O3^viii	0.83 (2)	1.87 (2)	2.6906 (12)	168 (2)

Symmetry codes: (ii) x−1/2, −y+1/2, z−1; (iii) x−1/2, −y+1/2, z; (iv) −x+1/2, y+1/2, −z+1; (v) x, y, z−1; (vi) x−1, y, z−1; (vii) −x, −y, −z+1; (viii) −x+1/2, y−1/2, −z+1.