Terbium(III) hydrogendiphosphate(V) tetra­hydrate

The Tb atom of the title compound, TbHP₂O₇·4H₂O, is coordinated by the O atoms of three symmetrically independent water mol­ecules and by five O atoms belonging to HP₂O₇⁻ groups. The TbO₈ polyhedra are inter­connected by the diphospate anions, forming a three-dimensional network which is additionally stabilized by O—H...O hydrogen bonding between water mol­ecules and O atoms of the HP₂O₇⁻ anions. Uncoordinated water mol­ecules are situated in channels and are connected via hydrogen bonds with the framework.

Key indicators

• Single-crystal X-ray study
• T = 295 K
• Mean [sigma](P-O) = 0.002 Å
• R factor = 0.012
• wR factor = 0.034
• Data-to-parameter ratio = 11.9

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT417_ALERT_2_B Short Inter D-H..H-D       H41    ..  H112    ..       1.94 Ang.

Alert level C
PLAT220_ALERT_2_C Large Non-Solvent    O     Ueq(max)/Ueq(min) ...       2.97 Ratio

Alert level G
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......         10

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

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 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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S1. Comment

Acidic rare earth diphosphates of general formula REHP₂O₇^.nH₂O exhibit interesting luminescent and optical properties (Hraiech et al., 2005 and references herein). The title compound is isostructural with other compounds of formula type REHP₂O₇^.4H₂O, RE = Sm (Chehimi-Moumen et al., 2002), Gd (Hraiech et al., 2005), and Eu (Anna-Rabah et al., 2006).

The structure of TbHP₂O₇^.4H₂O is made up of TbO₈ polyhedra and HP₂O₇ groups that form a three-dimensional framework. In channels running along a (Fig. 2) free water molecules are located which are connected via hydrogen bonds with the framework (see hydrogen-bonding Table).

The P₂O₇ group is protonated, with the H atom located at O4 (Fig. 1), as also indicated by elongation of the corresponding P—O distance. The bridging angle P1—O7—P2 between the two PO₄ tetrahedra is 130.73 (11)°.

Related literature

Isostructural compounds of the type REHP₂O₇.4H₂O were reported for RE = Sm by Chehimi-Moumen et al. (2002), for RE = Gd by Hraiech et al. (2005) and for RE = Eu by Anna-Rabah et al. (2006).

S2. Experimental

An aqueous solution of TbCl₃^.6H₂O (0.1M) was added dropwise to anhydrous Na₄P₂O₇ dissolved in destilled water (0.1M). The pH of the mixture was controlled with diluted hydrochloric acid to be slightly acidic, and the solution was stirred for two h at room temperature. Prismatic-shaped colourless crystals with a maximal size of 0.3 mm formed after a few days on slow evaporation.

S3. Refinement

The H atoms were localized from a difference Fourier map. Their coordinates were refined independently with O—H distances restrained to 0.82 (1) Å. The isotropic temperature parameters of the H atoms were refined with 1.2U_eq of the parent atom. The H111—O11—H112 angle of the free water molecule was restrained to 109.47 (10)°.

Computing details

Data collection: CrysAlis CCD (Oxford Diffraction, 2005); cell refinement: CrysAlis RED (Oxford Diffraction, 2005); data reduction: CrysAlis RED (Oxford Diffraction, 2005); program(s) used to solve structure: SIR2002 (Burla et al., 2003); program(s) used to refine structure: JANA2000 (Petříček et al., 2007); molecular graphics: DIAMOND (Brandenburg & Putz, 2005); software used to prepare material for publication: JANA2000 (Petříček et al., 2007).

Figures

Fig. 1. Part of the structure of HTbP2O7^.4H2O drawn with displacement ellipsoids at the 50% probability level. [Symmetry codes: (i) 1 + x, y, z; (ii) 1.5 - x, -1/2 + y, 1.5 - z; (iii) 1 - x, 1 - y, 2 - z]

Fig. 2. The packing of TbHP2O7^.4H2O viewed along a. Hydrogen bonds are represented by dashed lines. Colour code: Pink (P2O7 polyhedra), red spheres (O), grey spheres (Tb), dark grey spheres (H). All atoms are displayed with arbitrary radii. For clarity, O atoms belonging to PO4 tetrahedra have a smaller size than O atoms of water molecules. O atoms that would obscure H atoms important for understanding the hydrogen bonding scheme are plotted semitransparently.

Terbium(III) hydrogendiphosphate(V) tetrahydrate

Crystal data

TbHP2O7·4H2O	F(000) = 768
Mr = 405.9	Dx = 3.037 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71069 Å
Hall symbol: -P 2yn	Cell parameters from 972 reflections
a = 6.6006 (6) Å	θ = 2.5–26.5°
b = 11.4744 (9) Å	µ = 8.38 mm^−1
c = 11.7252 (13) Å	T = 295 K
β = 92.150 (8)°	Prism, colorless
V = 887.42 (15) Å^3	0.14 × 0.06 × 0.03 mm
Z = 4

Data collection

Oxford Diffraction CCD diffractometer	1850 independent reflections
Radiation source: X-ray tube	1628 reflections with I > 3σ(I)
Graphite monochromator	Rint = 0.019
Detector resolution: 8.3438 pixels mm^-1	θmax = 26.6°, θmin = 2.5°
ω scans	h = −8→7
Absorption correction: analytical [CrysAlis RED (Oxford Diffraction, 2005), using a multifaceted crystal model based on expressions derived by Clark & Reid (1995)]	k = −14→14
Tmin = 0.329, Tmax = 0.635	l = −14→14
8671 measured reflections

Refinement

Refinement on F^2	H atoms treated by a mixture of independent and constrained refinement
R[F^2 > 2σ(F^2)] = 0.011	Weighting scheme based on measured s.u.'s w = 1/[σ^2(I) + 0.0004I^2]
wR(F^2) = 0.034	(Δ/σ)max = 0.009
S = 1.21	Δρmax = 0.29 e Å^−3
1850 reflections	Δρmin = −0.21 e Å^−3
155 parameters	Extinction correction: B-C type 1 Lorentzian isotropic [Becker, P. J. & Coppens, P. (1974). Acta Cryst. A30, 129–147]
10 restraints	Extinction coefficient: 2.9 (8)
9 constraints

Special details

Refinement. The refinement was carried out against all reflections. The conventional R-factor is always based on F. The goodness of fit as well as the weighted R-factor are based on F and F² for refinement carried out on F and F², respectively. The threshold expression is used only for calculating R-factors etc. and it is not relevant to the choice of reflections for refinement.

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 may be larger then the ones from the SHELX program.

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

	x	y	z	Uiso*/Ueq
Tb1	0.755557 (17)	0.417027 (10)	0.836213 (10)	0.00831 (5)
P1	0.25551 (9)	0.54805 (6)	0.85787 (5)	0.00834 (18)
P2	0.47954 (9)	0.63300 (5)	0.66266 (5)	0.00860 (18)
O1	0.4213 (3)	0.45787 (15)	0.87403 (15)	0.0122 (5)
O2	0.0629 (3)	0.50007 (16)	0.80317 (16)	0.0157 (5)
O3	0.2158 (3)	0.61576 (15)	0.96588 (15)	0.0149 (5)
O4	0.3423 (3)	0.57670 (15)	0.56618 (17)	0.0169 (6)
O5	0.6553 (3)	0.55618 (15)	0.69557 (16)	0.0137 (5)
O6	0.5259 (2)	0.75465 (15)	0.62791 (15)	0.0135 (5)
O7	0.3378 (3)	0.64547 (14)	0.77094 (14)	0.0112 (5)
O8	0.7671 (3)	0.62083 (18)	0.93419 (17)	0.0177 (6)
O9	0.8201 (4)	0.34050 (17)	0.64753 (17)	0.0252 (7)
O10	0.5535 (3)	0.24098 (19)	0.8262 (2)	0.0333 (7)
O11	0.2577 (4)	0.36300 (19)	0.5980 (2)	0.0394 (9)
H81	0.697 (4)	0.614 (3)	0.9904 (18)	0.0212*
H111	0.294 (4)	0.3021 (18)	0.572 (3)	0.0472*
H82	0.881 (2)	0.643 (3)	0.955 (2)	0.0212*
H112	0.141 (2)	0.375 (3)	0.577 (3)	0.0472*
H101	0.593 (5)	0.1757 (15)	0.810 (3)	0.04*
H91	0.776 (5)	0.380 (3)	0.593 (2)	0.0303*
H92	0.777 (4)	0.2742 (13)	0.633 (3)	0.0303*
H41	0.323 (4)	0.5072 (10)	0.574 (3)	0.0203*
H102	0.434 (2)	0.243 (3)	0.807 (3)	0.04*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Tb1	0.00694 (8)	0.00827 (8)	0.00975 (8)	0.00064 (4)	0.00087 (5)	0.00041 (4)
P1	0.0067 (3)	0.0093 (3)	0.0092 (3)	0.0008 (2)	0.0021 (2)	0.0011 (2)
P2	0.0082 (3)	0.0085 (3)	0.0092 (3)	−0.0007 (2)	0.0009 (2)	0.0011 (2)
O1	0.0097 (9)	0.0127 (8)	0.0146 (9)	0.0029 (7)	0.0037 (7)	0.0037 (7)
O2	0.0095 (9)	0.0182 (9)	0.0192 (10)	−0.0040 (7)	−0.0004 (8)	0.0001 (7)
O3	0.0201 (10)	0.0137 (8)	0.0110 (10)	0.0048 (8)	0.0034 (7)	−0.0010 (7)
O4	0.0225 (11)	0.0120 (9)	0.0157 (10)	−0.0038 (8)	−0.0041 (8)	−0.0012 (7)
O5	0.0113 (9)	0.0156 (9)	0.0143 (10)	0.0031 (7)	0.0031 (8)	0.0039 (7)
O6	0.0141 (9)	0.0107 (8)	0.0159 (9)	−0.0034 (7)	0.0016 (7)	0.0022 (7)
O7	0.0115 (9)	0.0091 (8)	0.0133 (9)	0.0003 (7)	0.0055 (7)	0.0018 (7)
O8	0.0163 (11)	0.0208 (10)	0.0160 (11)	−0.0033 (9)	0.0013 (8)	0.0035 (8)
O9	0.0432 (13)	0.0160 (10)	0.0159 (11)	0.0057 (10)	−0.0061 (9)	−0.0017 (8)
O10	0.0138 (10)	0.0163 (10)	0.0697 (17)	−0.0019 (9)	−0.0005 (11)	−0.0122 (11)
O11	0.0541 (17)	0.0120 (11)	0.0542 (16)	−0.0102 (10)	0.0317 (14)	−0.0094 (10)

Geometric parameters (Å, º)

Tb1—O1	2.3145 (17)	P1—O1	1.5129 (18)
Tb1—O2^i	2.2877 (17)	P1—O2	1.5063 (18)
Tb1—O3^ii	2.3514 (18)	P1—O3	1.5169 (19)
Tb1—O5	2.3718 (18)	P1—O7	1.6201 (18)
Tb1—O6^iii	2.3842 (17)	P2—O4	1.562 (2)
Tb1—O8	2.605 (2)	P2—O5	1.4957 (19)
Tb1—O9	2.433 (2)	P2—O6	1.4891 (18)
Tb1—O10	2.421 (2)	P2—O7	1.6116 (18)
O1—Tb1—O2^i	143.70 (6)	O6^iii—Tb1—O8	128.03 (6)
O1—Tb1—O3^ii	83.41 (6)	O6^iii—Tb1—O9	75.70 (7)
O1—Tb1—O5	75.74 (6)	O6^iii—Tb1—O10	71.65 (6)
O1—Tb1—O6^iii	134.37 (6)	O8—Tb1—O9	136.20 (6)
O1—Tb1—O8	75.29 (6)	O8—Tb1—O10	141.01 (7)
O1—Tb1—O9	116.61 (7)	O9—Tb1—O10	76.69 (8)
O1—Tb1—O10	69.56 (7)	O1—P1—O2	113.46 (10)
O2^i—Tb1—O3^ii	101.23 (6)	O1—P1—O3	113.12 (10)
O2^i—Tb1—O5	80.10 (6)	O1—P1—O7	107.03 (10)
O2^i—Tb1—O6^iii	79.67 (6)	O2—P1—O3	111.92 (11)
O2^i—Tb1—O8	71.90 (6)	O2—P1—O7	106.35 (10)
O2^i—Tb1—O9	79.03 (7)	O3—P1—O7	104.14 (10)
O2^i—Tb1—O10	146.08 (7)	O4—P2—O5	111.48 (10)
O3^ii—Tb1—O5	143.50 (6)	O4—P2—O6	107.99 (10)
O3^ii—Tb1—O6^iii	71.04 (6)	O4—P2—O7	105.60 (10)
O3^ii—Tb1—O8	73.05 (6)	O5—P2—O6	117.25 (10)
O3^ii—Tb1—O9	146.04 (7)	O5—P2—O7	108.46 (10)
O3^ii—Tb1—O10	86.44 (8)	O6—P2—O7	105.28 (10)
O5—Tb1—O6^iii	143.13 (6)	H81—O8—H82	109 (3)
O5—Tb1—O8	72.85 (6)	H91—O9—H92	104 (3)
O5—Tb1—O9	70.39 (6)	H101—O10—H102	106 (3)
O5—Tb1—O10	112.90 (7)	H111—O11—H112	109 (3)

Symmetry codes: (i) x+1, y, z; (ii) −x+1, −y+1, −z+2; (iii) −x+3/2, y−1/2, −z+3/2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O4—H41···O11	0.813 (13)	1.736 (14)	2.546 (3)	174 (3)
O8—H81···O1^ii	0.82 (2)	1.98 (3)	2.762 (3)	159 (3)
O8—H82···O3^i	0.822 (18)	2.231 (14)	2.972 (3)	150 (3)
O9—H91···O4^iv	0.83 (3)	2.06 (3)	2.851 (3)	161 (3)
O9—H92···O8^iii	0.828 (18)	1.95 (2)	2.750 (3)	164 (3)
O10—H101···O5^iii	0.82 (2)	2.16 (3)	2.880 (3)	147 (3)
O10—H102···O7^v	0.812 (16)	2.28 (2)	2.991 (3)	147 (3)
O11—H111···O3^v	0.80 (2)	2.18 (2)	2.941 (3)	157 (3)

Symmetry codes: (i) x+1, y, z; (ii) −x+1, −y+1, −z+2; (iii) −x+3/2, y−1/2, −z+3/2; (iv) −x+1, −y+1, −z+1; (v) −x+1/2, y−1/2, −z+3/2.