Terbium hydrogendiphosphate trihydrate: synthesis and non-merohedral twinning

The title compound, Tb(HP₂O₇)·3H₂O, is isostructural with Y(HP₂O₇)·3H₂O and Gd(HP₂O₇)·3H₂O. The crystal studied exhibited non-merohedral twinning.

Key indicators

• Single-crystal X-ray study
• T = 294 K
• Mean [sigma](P-O) = 0.003 Å
• H-atom completeness 72%
• Disorder in main residue
• R factor = 0.026
• wR factor = 0.056
• Data-to-parameter ratio = 23.6

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT021_ALERT_1_B Ratio Unique / Expected Reflections too High ...       1.89

Alert level C
PLAT041_ALERT_1_C Calc. and Rep. SumFormula Strings    Differ ....          ?
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ ....          ?
PLAT154_ALERT_1_C The su's on the Cell Angles are Equal (x 10000)         600 Deg.
PLAT213_ALERT_2_C Atom O1      has ADP max/min Ratio .............       3.50 oblat
PLAT220_ALERT_2_C Large Non-Solvent    O     Ueq(max)/Ueq(min) ...       2.56 Ratio
PLAT301_ALERT_3_C Main Residue  Disorder .........................       3.00 Perc.
PLAT311_ALERT_2_C Isolated Disordered Oxygen Atom (No H's ?) .....       >O11

Alert level G
FORMU01_ALERT_2_G  There is a discrepancy between the atom counts in the
            _chemical_formula_sum and the formula from the _atom_site* data.
            Atom count from _chemical_formula_sum:H7 O10 P2 Tb1
            Atom count from the _atom_site data:  H5 O10 P2 Tb1
CELLZ01_ALERT_1_G Difference between formula and atom_site contents detected.
CELLZ01_ALERT_1_G WARNING: H atoms missing from atom site list. Is this intentional?
           From the CIF: _cell_formula_units_Z    2
           From the CIF: _chemical_formula_sum  H7 O10 P2 Tb1
           TEST: Compare cell contents of formula and atom_site data

           atom    Z*formula  cif sites diff
           H         14.00     10.00    4.00
           O         20.00     20.00    0.00
           P          4.00      4.00    0.00
           Tb         2.00      2.00    0.00

   0 ALERT level A = In general: serious problem
   1 ALERT level B = Potentially serious problem
   7 ALERT level C = Check and explain
   3 ALERT level G = General alerts; check

   6 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   4 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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Computing details

Data collection: CrysAlis CCD (Oxford Diffraction, 2005); cell refinement: CrysAlis RED (Oxford Diffraction, 2005); data reduction: CrysAlis RED; program(s) used to solve structure: SIR2002 (Burla et al., 2003); program(s) used to refine structure: JANA2000 (Petricek et al., 2000); molecular graphics: DIAMOND (Brandenburg & Putz, 2005); software used to prepare material for publication: JANA2000.

terbium hydrogendiphosphate trihydrate

Crystal data

Tb(HP2O7)·3H2O	Z = 2
Mr = 387.9	F(000) = 360
Triclinic, P1	Dx = 2.991 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71069 Å
a = 6.4551 (5) Å	Cell parameters from 10460 reflections
b = 6.9597 (4) Å	θ = 3.2–26.6°
c = 9.8253 (7) Å	µ = 8.61 mm^−1
α = 81.621 (6)°	T = 294 K
β = 80.464 (6)°	Prism, colorless
γ = 88.341 (6)°	0.08 × 0.05 × 0.02 mm
V = 430.66 (5) Å^3

Data collection

Oxford Diffraction CCD diffractometer	3399 independent reflections
Radiation source: X-ray tube	2737 reflections with I > 3σ(I)
Graphite monochromator	Rint = 0.049
Detector resolution: 8.3438 pixels mm^-1	θmax = 26.6°, θmin = 3.2°
Rotation method data acquisition using ω scans	h = −8→8
Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2005)	k = −8→8
Tmin = 0.419, Tmax = 0.659	l = −12→12
10460 measured reflections

Refinement

Refinement on F^2	5 constraints
R[F > 3σ(F)] = 0.026	H atoms treated by a mixture of independent and constrained refinement
wR(F) = 0.056	Weighting scheme based on measured s.u.'s w = 1/[σ^2(I) + 0.0004I^2]
S = 1.13	(Δ/σ)max = 0.019
3399 reflections	Δρmax = 0.97 e Å^−3
144 parameters	Δρmin = −0.66 e Å^−3
6 restraints

Special details

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors are based on F, with F set to zero for negative F². The threshold expression of F² > n*σ(F²) is used only for calculating R-factors etc. and is not relevant to the choice of reflections for refinement.

The hydrogen atoms were localized from the difference Fourier map. Their coordinates were refined independently. The O—H distances were restrained to 0.82 Å with σ 0.01. The isotropic temperature parameters of hydrogen atoms were calculated as 1.2*U_eq of the parent atom.

The structure was a twin with partial overlaps of reflections. Both twin domains were used in the refinement. The angular limit for complete overlap was chosen 0.1°.

One water molecule was disordered. The oxygen of this molecule was split in two partially occupied positions clearly visible in the difference Fourier map. The occupation of the split positions was refined. The ADP parameters of split O atoms were kept identical. The hydrogen atoms of the disordered water molecule could not be determined.

The program used for refinement, Jana2000, uses the weighting scheme based on the experimental expectations, see _refine_ls_weighting_details, that does not force S to be one. Therefore the values of S are usually larger then the ones from the SHELX program.

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

	x	y	z	Uiso*/Ueq	Occ. (<1)
Tb1	0.37274 (4)	0.26131 (3)	0.45245 (3)	0.01008 (7)
P1	−0.19255 (17)	0.23305 (16)	0.56073 (12)	0.0088 (3)
P2	0.05658 (18)	0.14173 (17)	0.78786 (12)	0.0135 (4)
O1	−0.3366 (4)	0.4087 (4)	0.5581 (3)	0.0123 (10)
O2	−0.3303 (4)	0.0720 (4)	0.5328 (3)	0.0126 (10)
O3	0.0676 (5)	−0.0735 (4)	0.8359 (3)	0.0206 (11)
O4	0.0126 (4)	0.2583 (4)	0.4667 (3)	0.0137 (10)
O5	0.2409 (5)	0.2314 (5)	0.6891 (3)	0.0186 (11)
O6	−0.1506 (5)	0.1800 (5)	0.7171 (3)	0.0191 (11)
O7	0.0087 (6)	0.2585 (5)	0.9129 (3)	0.0261 (13)
O8	0.6688 (5)	0.3618 (5)	0.2657 (4)	0.0237 (13)
O9	0.2861 (6)	0.2700 (6)	0.2249 (4)	0.0317 (14)
O10	0.500 (2)	0.107 (3)	0.0007 (15)	0.103 (11)	0.452 (16)
O11	0.5102 (13)	0.327 (2)	−0.0466 (9)	0.066 (5)	0.548 (16)
H71	−0.031 (8)	0.198 (7)	0.990 (2)	0.0313*
H81	0.740 (7)	0.457 (5)	0.266 (5)	0.0284*
H82	0.732 (7)	0.260 (4)	0.255 (6)	0.0284*
H91	0.370 (7)	0.260 (8)	0.155 (4)	0.038*
H92	0.186 (6)	0.212 (7)	0.210 (6)	0.038*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Tb1	0.00869 (11)	0.00724 (12)	0.01377 (12)	0.00016 (7)	−0.00118 (8)	−0.00046 (8)
P1	0.0064 (5)	0.0068 (6)	0.0132 (6)	0.0006 (4)	−0.0026 (5)	−0.0006 (5)
P2	0.0126 (6)	0.0171 (7)	0.0106 (6)	−0.0015 (5)	−0.0025 (5)	−0.0006 (5)
O1	0.0083 (14)	0.0074 (16)	0.0206 (18)	0.0058 (12)	−0.0036 (14)	−0.0002 (13)
O2	0.0119 (15)	0.0078 (16)	0.0195 (18)	−0.0061 (12)	−0.0076 (14)	0.0009 (13)
O3	0.0313 (19)	0.0156 (18)	0.0141 (18)	0.0043 (15)	−0.0047 (16)	0.0013 (14)
O4	0.0076 (15)	0.0190 (17)	0.0144 (17)	0.0012 (13)	−0.0019 (13)	−0.0016 (13)
O5	0.0152 (16)	0.029 (2)	0.0108 (18)	−0.0040 (14)	−0.0027 (14)	0.0014 (14)
O6	0.0095 (16)	0.0235 (19)	0.025 (2)	0.0009 (14)	−0.0050 (15)	−0.0019 (15)
O7	0.046 (2)	0.020 (2)	0.0118 (19)	−0.0022 (17)	−0.0036 (18)	−0.0018 (15)
O8	0.0198 (19)	0.024 (2)	0.025 (2)	−0.0024 (15)	0.0029 (16)	−0.0046 (18)
O9	0.027 (2)	0.048 (3)	0.020 (2)	−0.0146 (19)	−0.0051 (17)	−0.0018 (19)
O10	0.046 (4)	0.142 (8)	0.042 (4)	0.014 (6)	0.007 (4)	−0.017 (5)
O11	0.046 (4)	0.142 (8)	0.042 (4)	0.014 (6)	0.007 (4)	−0.017 (5)

Geometric parameters (Å, º)

Tb1—O1^i	2.291 (3)	P2—O3	1.507 (3)
Tb1—O1^ii	2.592 (3)	P2—O5	1.494 (3)
Tb1—O2^ii	2.467 (3)	P2—O6	1.605 (3)
Tb1—O2^iii	2.324 (3)	P2—O7	1.554 (4)
Tb1—O4	2.306 (3)	O7—H71	0.82 (3)
Tb1—O5	2.321 (3)	O8—H81	0.82 (4)
Tb1—O8	2.459 (3)	O8—H82	0.82 (3)
Tb1—O9	2.385 (4)	O9—H91	0.81 (4)
P1—O1	1.514 (3)	O9—H92	0.82 (5)
P1—O2	1.533 (3)	O10—O10^iv	1.49 (3)
P1—O4	1.483 (3)	O10—O11	1.53 (3)
P1—O6	1.593 (4)
O1^ii—Tb1—O1^i	68.37 (10)	O2^iii—Tb1—O8	108.16 (11)
O1^ii—Tb1—O2^ii	56.34 (9)	O2^iii—Tb1—O9	84.07 (13)
O1^ii—Tb1—O2^iii	122.19 (10)	O4—Tb1—O5	74.87 (11)
O1^ii—Tb1—O4	141.03 (10)	O4—Tb1—O8	134.73 (11)
O1^ii—Tb1—O5	75.98 (10)	O4—Tb1—O9	70.49 (11)
O1^ii—Tb1—O8	70.91 (11)	O5—Tb1—O8	146.84 (12)
O1^ii—Tb1—O9	135.87 (11)	O5—Tb1—O9	145.19 (12)
O1^i—Tb1—O1^ii	68.37 (10)	O8—Tb1—O9	67.07 (12)
O1^i—Tb1—O2^ii	124.47 (10)	O1—P1—O2	103.35 (17)
O1^i—Tb1—O2^iii	167.52 (10)	O1—P1—O4	115.85 (16)
O1^i—Tb1—O4	85.58 (10)	O1—P1—O6	106.54 (18)
O1^i—Tb1—O5	88.58 (11)	O2—P1—O4	114.68 (18)
O1^i—Tb1—O8	80.95 (11)	O2—P1—O6	107.20 (17)
O1^i—Tb1—O9	92.01 (13)	O4—P1—O6	108.61 (17)
O2^ii—Tb1—O2^iii	66.97 (10)	O3—P2—O5	117.02 (18)
O2^ii—Tb1—O4	142.59 (9)	O3—P2—O6	106.99 (19)
O2^ii—Tb1—O5	83.42 (10)	O3—P2—O7	111.68 (18)
O2^ii—Tb1—O8	77.06 (10)	O5—P2—O6	109.19 (18)
O2^ii—Tb1—O9	123.40 (12)	O5—P2—O7	108.6 (2)
O2^iii—Tb1—O2^ii	66.97 (10)	O6—P2—O7	102.2 (2)
O2^iii—Tb1—O4	81.94 (10)	P2—O7—H71	118 (3)
O2^iii—Tb1—O5	87.93 (11)	O10^iv—O10—O11	162.3 (13)

Symmetry codes: (i) −x, −y+1, −z+1; (ii) x+1, y, z; (iii) −x, −y, −z+1; (iv) −x+1, −y, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O7—H71···O3^v	0.82 (3)	1.78 (3)	2.588 (4)	169 (5)
O8—H82···O3^vi	0.82 (3)	2.00 (4)	2.782 (5)	159 (5)
O9—H91···O11	0.81 (4)	2.03 (4)	2.795 (9)	157 (5)
O9—H92···O3^iii	0.82 (4)	2.07 (4)	2.883 (5)	177 (6)
O9—H91···O10	0.81 (4)	2.03 (5)	2.770 (17)	151 (5)

Symmetry codes: (iii) −x, −y, −z+1; (v) −x, −y, −z+2; (vi) −x+1, −y, −z+1.