Barium di­hydrogen phosphite hemihydrate

Ba(H₂PO₃)₂·0.5H₂O contains ninefold-coordinated Ba ions connected by di­hydrogen phosphite anions to form a three-dimensional network. The asymmetric unit contains two Ba²⁺ ions, four [H₂PO₃]^- ions and one water mol­ecule.

Key indicators

• Single-crystal X-ray study
• T = 173 K
• Mean [sigma](P-O) = 0.004 Å
• H-atom completeness 61%
• R factor = 0.036
• wR factor = 0.086
• Data-to-parameter ratio = 25.6

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

PLATON alerts of the form PLAT_7?? have been detected for an inorganic
structure. These tests are under development  for inorganics and
comments are welcomed. It is not necessary to supply a data
validation response form for these alerts at this time.


 Alert Level A:



PLAT_731  Alert A Bond    Calc     0.84(3), Rep  0.8400(10) ....       9.90 s.u-Ratio
                     O1   -H1A     1.555   1.555

PLAT_731  Alert A Bond    Calc     0.84(4), Rep  0.8400(10) ....       9.90 s.u-Ratio
                     O1   -H1B     1.555   1.555

PLAT_735  Alert A D-H     Calc     0.84(3), Rep  0.8400(10) ....       9.90 s.u-Ratio
                     O1   -H1A     1.555   1.555

PLAT_735  Alert A D-H     Calc     0.84(3), Rep  0.8400(10) ....       9.90 s.u-Ratio
                     O1   -H1A     1.555   1.555

PLAT_735  Alert A D-H     Calc     0.84(4), Rep  0.8400(10) ....       9.90 s.u-Ratio
                     O1   -H1B     1.555   1.555


 Alert Level B:



PLAT_736  Alert B H...A   Calc     1.99(5), Rep   1.986(12) ....       4.17 s.u-Ratio
                     H1B  -O12     1.555   2.645


 Alert Level C:



PLAT_420  Alert C D-H Without Acceptor       P(1)   -   H(1)              ?

PLAT_420  Alert C D-H Without Acceptor       P(2)   -   H(2)              ?

PLAT_420  Alert C D-H Without Acceptor       P(3)   -   H(3)              ?

PLAT_420  Alert C D-H Without Acceptor       P(4)   -   H(4)              ?

General Notes



FORMU_01  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:H5 Ba1 O6.5 P2
          Atom count from the _atom_site data:  H3 Ba1 O6.5 P2

CELLZ_01
         From the CIF: _cell_formula_units_Z    8
         From the CIF: _chemical_formula_sum  Ba H5 O6.50 P2
         TEST: Compare cell contents of formula and atom_site data

         atom    Z*formula  cif sites diff
         Ba         8.00      8.00    0.00
         H         40.00     24.00   16.00
         O         52.00     52.00    0.00
         P         16.00     16.00    0.00
          Difference between formula and atom_site contents detected.
          WARNING: H atoms missing from atom site list. Is this intentional?


 5 Alert Level A = Potentially serious problem

 1 Alert Level B = Potential problem

 4 Alert Level C = Please check

---

S1. Comment

Crystal structure analyses of alkaline-earth dihydrogen phosphites have been taking place for several decades (Ouarsal et al., 2002, and references therein). Continuing these investigations, we report here the structure of Ba(H₂PO₃)₂·0.5H₂O. Fig. 1 shows the asymmetric unit. The Ba ions occupy two different ninefold-coordinated sites. The coordination of Ba1 is made up of seven monodentate dihydrogen phosphite groups and two O atoms from two water molecules. Ba2 is surrounded by six monodentate and one bidentate dihydrogen phosphite ligands. The average d_Ba—O is 2.83 (11) and 2.86 (10) Å, respectively. In BaZn₃(HPO₃)₄·6H₂O, Ba is twelvefold-coordinated with d_Ba—O ranging from 2.876 to 3.053 Å (Ortiz-Avila et al., 1989). Two neighbouring BaO₉ units, related by a centre of symmetry, share an O–O edge, to form a Ba₂O₁₆ dimer. Two such dimers are joined through an edge (O33–O43) and a face (O41–O23–O32) to build up a double channel parallel to [010] (Fig. 2). There are four crystallographically independent phosphorus centres each tetrahedrally coordinated to one H and three O atoms. The P—O bond distances are in the usual range, similar to those reported in Sr(H₂PO₃)₂ (Ouarsal et al., 2002).

S2. Experimental

25 ml of BaCl₂·6H₂O (0.1 M) and 25 ml of phosphorous acid (1 M) were mixed in water. The mixture was stirred for 8 h at 333 K before being left at room temperature. After a few days, colourless crystals were deposited. These were filtered off and washed with a solution of ethanol (80%).

S3. Refinement

The water H atoms were located in a difference Fourier synthesis and were refined freely constraining the O—H distance to 0.84 Å. H atoms bonded to P were refined with fixed individual displacement parameters [U(H) = 1.2 U_eq(P)] using a riding model with P—H = 1.30 Å. The H atoms bonded to O of the dihydrogen phosphite ions could not be located and were omitted from the refinement. The highest ten peaks in the difference electron density map are located close (~1 Å) to the Ba atoms. The deepest hole is at 0.69 Å from Ba1.

Computing details

Data collection: X-AREA (Stoe & Cie, 2001); cell refinement: X-AREA; data reduction: X-AREA; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP in SHELXTL-Plus (Sheldrick, 1991).

Figures

	Fig. 1. Perspective view of the asymmetric unit of the title compound with the atom numbering; displacement ellipsoids are at the 50% probability level. Symmetry operators for equivalent atoms: (i) 1.5 - x, -0.5 + y, 1.5 - z; (ii) 1 - x, 1 - y, 1 - z; (iii) 2 - x, 1 - y, 1 - z; (iv) 2 - x, -y, 1 - z; (v) 1.5 - x, -0.5 + y, 0.5 - z; (vi) x, -1 + y, z; (vii) 1 - x, -y, 1 - z.
	Fig. 2. Packing diagram of the title compound.

barium dihydrogen phosphite hemihydrate

Crystal data

Ba(H2PO3)2·0.5H2O	F(000) = 1144
Mr = 308.32	Dx = 2.974 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 32287 reflections
a = 11.2351 (8) Å	θ = 4.0–32.7°
b = 8.7244 (5) Å	µ = 6.21 mm^−1
c = 14.0518 (9) Å	T = 173 K
β = 90.493 (6)°	Plate, colourless
V = 1377.30 (15) Å^3	0.28 × 0.18 × 0.05 mm
Z = 8

Data collection

STOE IPDS-II two-circle diffractometer	4582 independent reflections
Radiation source: fine-focus sealed tube	3635 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.097
ω scans	θmax = 31.5°, θmin = 3.7°
Absorption correction: empirical (using intensity measurements) (MULABS; Spek, 1990; Blessing, 1995)	h = −16→16
Tmin = 0.275, Tmax = 0.747	k = −12→12
38630 measured reflections	l = −20→20

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)] = 0.036	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.086	w = 1/[σ^2(Fo^2) + (0.0533P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 0.93	(Δ/σ)max = 0.002
4582 reflections	Δρmax = 2.01 e Å^−3
179 parameters	Δρmin = −1.79 e Å^−3
2 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0045 (3)

Special details

Experimental. ;

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
Ba1	0.79743 (2)	0.02237 (3)	0.522038 (17)	0.01404 (7)
O1	0.9680 (3)	−0.0638 (4)	0.3813 (3)	0.0208 (6)
H1A	0.947 (6)	−0.156 (2)	0.387 (5)	0.025*
H1B	0.937 (6)	−0.039 (8)	0.329 (2)	0.025*
Ba2	0.74023 (2)	0.50599 (3)	0.519360 (18)	0.01443 (7)
P1	0.75415 (11)	0.64078 (13)	0.26576 (8)	0.0162 (2)
H1	0.7216	0.7806	0.2471	0.019*
P2	0.67811 (11)	0.76867 (12)	0.75045 (8)	0.0160 (2)
H2	0.5631	0.7844	0.7480	0.019*
P3	0.50060 (10)	0.22587 (13)	0.54280 (8)	0.0159 (2)
H3	0.5208	0.1248	0.6090	0.019*
P4	0.99914 (10)	0.69045 (13)	0.60405 (8)	0.0144 (2)
H4	0.9914	0.7554	0.6870	0.017*
O11	0.8120 (3)	0.5712 (4)	0.1731 (2)	0.0218 (7)
O12	0.6436 (3)	0.5476 (4)	0.2852 (3)	0.0252 (7)
O13	0.8416 (3)	0.6451 (4)	0.3474 (3)	0.0218 (7)
O21	0.7326 (4)	0.9117 (4)	0.6995 (3)	0.0247 (7)
O22	0.7079 (4)	0.6257 (4)	0.6943 (2)	0.0206 (7)
O23	0.7154 (3)	0.7630 (4)	0.8537 (2)	0.0180 (6)
O31	0.5128 (3)	0.3905 (4)	0.5898 (3)	0.0244 (7)
O32	0.6016 (3)	0.2174 (4)	0.4734 (2)	0.0209 (6)
O33	0.3762 (3)	0.2028 (4)	0.5077 (3)	0.0221 (7)
O41	1.1243 (3)	0.7144 (4)	0.5691 (2)	0.0178 (6)
O42	0.9712 (3)	0.5141 (4)	0.6175 (3)	0.0229 (7)
O43	0.8988 (3)	0.7503 (4)	0.5435 (2)	0.0180 (6)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ba1	0.01557 (12)	0.01173 (11)	0.01482 (12)	0.00049 (8)	0.00072 (8)	0.00039 (8)
O1	0.0238 (17)	0.0181 (14)	0.0205 (16)	0.0003 (13)	0.0001 (13)	0.0001 (12)
Ba2	0.01589 (12)	0.01207 (11)	0.01535 (12)	−0.00013 (8)	0.00052 (8)	−0.00045 (7)
P1	0.0182 (5)	0.0149 (4)	0.0155 (5)	0.0014 (4)	0.0000 (4)	−0.0002 (4)
P2	0.0218 (5)	0.0122 (4)	0.0140 (5)	0.0004 (4)	0.0006 (4)	−0.0004 (3)
P3	0.0154 (5)	0.0150 (5)	0.0171 (5)	0.0002 (4)	0.0005 (4)	−0.0002 (4)
P4	0.0147 (5)	0.0134 (4)	0.0151 (5)	−0.0006 (4)	0.0002 (4)	0.0000 (3)
O11	0.0245 (17)	0.0222 (16)	0.0189 (15)	−0.0026 (13)	0.0039 (13)	0.0013 (12)
O12	0.0238 (17)	0.0255 (16)	0.0265 (18)	−0.0024 (14)	0.0066 (14)	−0.0061 (14)
O13	0.0254 (17)	0.0225 (15)	0.0174 (15)	0.0050 (13)	−0.0047 (13)	−0.0016 (12)
O21	0.041 (2)	0.0158 (14)	0.0169 (15)	−0.0044 (14)	0.0049 (14)	−0.0001 (12)
O22	0.0349 (19)	0.0129 (13)	0.0140 (14)	0.0030 (13)	0.0004 (13)	−0.0010 (11)
O23	0.0230 (15)	0.0159 (13)	0.0152 (14)	−0.0002 (12)	0.0006 (11)	−0.0010 (11)
O31	0.0253 (17)	0.0218 (16)	0.0263 (18)	−0.0049 (13)	0.0069 (14)	−0.0083 (13)
O32	0.0204 (15)	0.0246 (16)	0.0179 (15)	0.0025 (13)	0.0023 (12)	−0.0024 (12)
O33	0.0171 (15)	0.0217 (15)	0.0276 (18)	0.0003 (12)	−0.0010 (13)	0.0006 (13)
O41	0.0171 (14)	0.0151 (13)	0.0212 (15)	−0.0010 (11)	0.0006 (11)	0.0017 (11)
O42	0.0188 (15)	0.0150 (14)	0.0348 (19)	−0.0030 (12)	−0.0013 (13)	0.0069 (13)
O43	0.0159 (14)	0.0153 (13)	0.0227 (16)	0.0009 (11)	−0.0010 (11)	0.0016 (11)

Geometric parameters (Å, º)

Ba1—O43^i	2.649 (3)	Ba2—O13	2.942 (4)
Ba1—O23^ii	2.736 (3)	Ba2—O32	3.028 (4)
Ba1—O41^iii	2.776 (3)	P1—O13	1.504 (4)
Ba1—O21^i	2.777 (3)	P1—O12	1.511 (4)
Ba1—O33^iv	2.797 (4)	P1—O11	1.582 (4)
Ba1—O32	2.859 (4)	P1—H1	1.3000
Ba1—O1	2.866 (4)	P2—O23	1.507 (3)
Ba1—O1^v	2.976 (4)	P2—O22	1.515 (3)
Ba1—O11^vi	3.025 (4)	P2—O21	1.566 (4)
Ba1—Ba2	4.2681 (4)	P2—H2	1.3000
O1—H1A	0.8400 (10)	P3—O33	1.492 (4)
O1—H1B	0.8400 (10)	P3—O32	1.505 (4)
Ba2—O22	2.698 (3)	P3—O31	1.586 (4)
Ba2—O41^iii	2.755 (3)	P3—H3	1.3000
Ba2—O43	2.797 (3)	P4—O43	1.500 (3)
Ba2—O23^ii	2.812 (3)	P4—O41	1.508 (3)
Ba2—O33^vii	2.881 (4)	P4—O42	1.582 (3)
Ba2—O31	2.927 (4)	P4—H4	1.3000
Ba2—O42	2.929 (4)
O43^i—Ba1—O23^ii	129.80 (10)	O43—Ba2—O31	141.11 (10)
O43^i—Ba1—O41^iii	131.00 (10)	O23^ii—Ba2—O31	71.14 (11)
O23^ii—Ba1—O41^iii	71.23 (10)	O33^vii—Ba2—O31	87.20 (10)
O43^i—Ba1—O21^i	72.67 (11)	O22—Ba2—O42	71.79 (11)
O23^ii—Ba1—O21^i	71.22 (10)	O41^iii—Ba2—O42	74.85 (10)
O41^iii—Ba1—O21^i	142.04 (10)	O43—Ba2—O42	50.48 (9)
O43^i—Ba1—O33^iv	71.72 (10)	O23^ii—Ba2—O42	64.40 (10)
O23^ii—Ba1—O33^iv	126.42 (10)	O33^vii—Ba2—O42	116.11 (10)
O41^iii—Ba1—O33^iv	137.34 (10)	O31—Ba2—O42	128.44 (11)
O21^i—Ba1—O33^iv	72.65 (11)	O22—Ba2—O13	130.13 (10)
O43^i—Ba1—O32	152.82 (10)	O41^iii—Ba2—O13	72.43 (10)
O23^ii—Ba1—O32	69.60 (10)	O43—Ba2—O13	62.26 (10)
O41^iii—Ba1—O32	69.13 (10)	O23^ii—Ba2—O13	139.84 (10)
O21^i—Ba1—O32	102.38 (11)	O33^vii—Ba2—O13	72.93 (10)
O33^iv—Ba1—O32	81.26 (11)	O31—Ba2—O13	139.88 (11)
O43^i—Ba1—O1	63.51 (10)	O42—Ba2—O13	91.68 (10)
O23^ii—Ba1—O1	132.92 (10)	O22—Ba2—O32	116.32 (10)
O41^iii—Ba1—O1	71.47 (10)	O41^iii—Ba2—O32	66.95 (9)
O21^i—Ba1—O1	135.27 (11)	O43—Ba2—O32	170.30 (9)
O33^iv—Ba1—O1	100.52 (10)	O23^ii—Ba2—O32	66.21 (10)
O32—Ba1—O1	120.58 (10)	O33^vii—Ba2—O32	118.24 (10)
O43^i—Ba1—O1^v	71.26 (10)	O31—Ba2—O32	48.47 (9)
O23^ii—Ba1—O1^v	70.53 (10)	O42—Ba2—O32	124.93 (9)
O41^iii—Ba1—O1^v	80.06 (10)	O13—Ba2—O32	111.70 (10)
O21^i—Ba1—O1^v	82.55 (11)	O13—P1—O12	114.1 (2)
O33^iv—Ba1—O1^v	140.08 (10)	O13—P1—O11	111.5 (2)
O32—Ba1—O1^v	135.50 (10)	O12—P1—O11	106.6 (2)
O1—Ba1—O1^v	75.64 (11)	O13—P1—H1	108.1
O43^i—Ba1—O11^vi	113.59 (10)	O12—P1—H1	108.1
O23^ii—Ba1—O11^vi	116.57 (10)	O11—P1—H1	108.1
O41^iii—Ba1—O11^vi	66.01 (10)	O23—P2—O22	114.46 (19)
O21^i—Ba1—O11^vi	139.03 (11)	O23—P2—O21	111.1 (2)
O33^iv—Ba1—O11^vi	71.71 (10)	O22—P2—O21	109.2 (2)
O32—Ba1—O11^vi	52.68 (9)	O23—P2—H2	107.3
O1—Ba1—O11^vi	71.37 (10)	O22—P2—H2	107.3
O1^v—Ba1—O11^vi	138.40 (10)	O21—P2—H2	107.3
O22—Ba2—O41^iii	139.51 (11)	O33—P3—O32	119.2 (2)
O22—Ba2—O43	71.65 (11)	O33—P3—O31	109.7 (2)
O41^iii—Ba2—O43	103.45 (10)	O32—P3—O31	104.6 (2)
O22—Ba2—O23^ii	74.84 (10)	O33—P3—H3	107.6
O41^iii—Ba2—O23^ii	70.41 (10)	O32—P3—H3	107.6
O43—Ba2—O23^ii	112.84 (10)	O31—P3—H3	107.6
O22—Ba2—O33^vii	73.38 (10)	O43—P4—O41	117.73 (19)
O41^iii—Ba2—O33^vii	143.89 (10)	O43—P4—O42	104.9 (2)
O43—Ba2—O33^vii	68.41 (10)	O41—P4—O42	111.12 (19)
O23^ii—Ba2—O33^vii	145.69 (10)	O43—P4—H4	107.5
O22—Ba2—O31	72.57 (11)	O41—P4—H4	107.5
O41^iii—Ba2—O31	113.57 (10)	O42—P4—H4	107.5

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1A···O13^i	0.84 (1)	2.17 (3)	2.947 (5)	153 (7)
O1—H1A···O43^i	0.84 (1)	2.41 (6)	2.909 (5)	118 (6)
O1—H1B···O12^vi	0.84 (1)	1.99 (1)	2.818 (5)	171 (7)

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