Penta­aqua­(di­chloro­methyl­enebis­phospho­nato)­strontium(II)

The title compound, [Sr{Cl₂C(PO₃H)₂}(H₂O)₅], is a monomer, the Sr atom being seven-coordinated by one chelating clodronate ligand and five aqua ligands. The coordination polyhedron can be described as a distorted monocapped trigonal prism. This compound is isostructural with hydrated calcium clodronate, [Ca{Cl₂C(PO₃H)₂}(H₂O)₅], described previously [Nardelli, Pelizzi, Staibano & Zucchi (1983). Inorg. Chim. Acta, 80, 259-271].

Key indicators

• Single-crystal X-ray study
• T = 120 K
• Mean [sigma](P-C) = 0.004 Å
• R factor = 0.019
• wR factor = 0.047
• Data-to-parameter ratio = 17.1

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT111_ALERT_2_B ADDSYM Detects (Pseudo) Centre of Symmetry .....        100 PerFit
PLAT112_ALERT_2_B ADDSYM Detects Additional (Pseudo) Symm. Elem...          m
PLAT113_ALERT_2_B ADDSYM Suggests Possible Pseudo/New Spacegroup .       Pnma

Alert level C
STRVA01_ALERT_4_C           Flack test results are ambiguous.
           From the CIF: _refine_ls_abs_structure_Flack    0.504
           From the CIF: _refine_ls_abs_structure_Flack_su    0.005
PLAT033_ALERT_2_C Flack Parameter Value Deviates from Zero .......       0.50
PLAT061_ALERT_3_C Tmax/Tmin Range Test RR' too Large .............       0.84
PLAT141_ALERT_4_C su on a - Axis Small or Missing (x 100000) .....         10 Ang.
PLAT142_ALERT_4_C su on b - Axis Small or Missing (x 100000) .....         10 Ang.
PLAT431_ALERT_2_C Short Inter HL..A Contact  Cl1    ..  Cl2     ..       3.28 Ang.

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           25.99
           From the CIF: _reflns_number_total               2674
           Count of symmetry unique reflns         1414
           Completeness (_total/calc)            189.11%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured      1260
           Fraction of Friedel pairs measured     0.891
           Are heavy atom types Z>Si present          yes

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

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   5 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
   4 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: COLLECT (Nonius, 1997); cell refinement: DENZO and SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO and SCALEPACK; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP in SHELXTL (Bruker, 1998); software used to prepare material for publication: SHELXL97.

Pentaaqua(dichloromethylenebisphosphonato)strontium(II)

Crystal data

[Sr(CH2Cl2O6P2)(H2O)5]	F(000) = 832
Mr = 420.57	Dx = 2.051 Mg m^−3 Dm = 2.02 (4) Mg m^−3 Dm measured by flotation
Orthorhombic, Pna21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2n	Cell parameters from 2674 reflections
a = 10.5207 (1) Å	θ = 2.6–26.0°
b = 11.8587 (1) Å	µ = 4.63 mm^−1
c = 10.9164 (2) Å	T = 120 K
V = 1361.95 (3) Å^3	Cubic, colourless
Z = 4	0.35 × 0.35 × 0.35 mm

Data collection

Nonius KappaCCD diffractometer	2674 independent reflections
Radiation source: fine-focus sealed tube	2596 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.057
CCD scans	θmax = 26.0°, θmin = 2.6°
Absorption correction: multi-scan (XPREP in SHELXTL; Bruker, 1998)	h = −12→12
Tmin = 0.182, Tmax = 0.198	k = −14→14
17202 measured reflections	l = −13→13

Refinement

Refinement on F^2	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F^2 > 2σ(F^2)] = 0.019	w = 1/[σ^2(Fo^2) + (0.02P)^2 + 0.6P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.047	(Δ/σ)max < 0.001
S = 1.08	Δρmax = 0.33 e Å^−3
2674 reflections	Δρmin = −0.56 e Å^−3
156 parameters	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
1 restraint	Extinction coefficient: 0.0028 (4)
Primary atom site location: structure-invariant direct methods	Absolute structure: Flack (1983), 1260 Fiedel pairs
Secondary atom site location: difference Fourier map	Absolute structure parameter: 0.504 (5)

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. There seems to be a pseudo

centre of symmetry in the structure, and therefore the structure was solved as racemic twin. The solution in centrosymmetric space group Pnma was not satisfactory: the disorder increased and the R-factors did not decrease.

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

	x	y	z	Uiso*/Ueq
Sr	0.014425 (17)	0.569776 (14)	0.39191 (3)	0.00876 (7)
Cl1	0.24388 (6)	0.31391 (4)	0.40347 (9)	0.02008 (14)
Cl2	0.51388 (6)	0.37227 (5)	0.40667 (9)	0.02025 (17)
P1	0.32978 (8)	0.51141 (7)	0.54358 (6)	0.00913 (17)
P2	0.33453 (9)	0.50493 (6)	0.25608 (7)	0.00942 (18)
O1	−0.1087 (2)	0.67833 (14)	0.22128 (17)	0.0146 (4)
H1A	−0.1835	0.6577	0.2021	0.022*
H1B	−0.1142	0.7420	0.2567	0.022*
O2	−0.15045 (19)	0.68067 (16)	0.51804 (18)	0.0156 (4)
H2A	−0.1162	0.7387	0.5497	0.023*
H2B	−0.1992	0.6516	0.5715	0.023*
O3	−0.0600 (3)	0.41653 (19)	0.5395 (2)	0.0156 (5)
H3A	−0.1221	0.4174	0.5893	0.023*
H3B	0.0064	0.3994	0.5797	0.023*
O4	−0.0889 (3)	0.4150 (2)	0.2685 (2)	0.0254 (7)
H4A	−0.1115	0.4196	0.1939	0.038*
H4B	−0.1183	0.3536	0.2970	0.038*
O5	0.10852 (14)	0.76722 (11)	0.3912 (2)	0.0159 (3)
H5A	0.1804	0.7859	0.4204	0.024*
H5B	0.0584	0.8228	0.4006	0.024*
O11	0.1952 (2)	0.55176 (18)	0.5393 (2)	0.0115 (5)
O12	0.4312 (2)	0.6005 (2)	0.54936 (19)	0.0107 (5)
O13	0.3443 (3)	0.42361 (17)	0.6500 (2)	0.0134 (5)
O21	0.2002 (2)	0.54300 (19)	0.2522 (2)	0.0149 (5)
O23	0.3542 (3)	0.41172 (18)	0.1563 (2)	0.0153 (5)
O22	0.4367 (2)	0.59286 (19)	0.25009 (18)	0.0108 (5)
C1	0.3565 (2)	0.42816 (15)	0.4027 (4)	0.0104 (5)
H13	0.4324	0.4201	0.6625	0.016*
H23	0.4158	0.4035	0.1066	0.016*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Sr	0.00701 (11)	0.01075 (10)	0.00851 (11)	0.00088 (6)	−0.00037 (15)	0.00048 (13)
Cl1	0.0216 (3)	0.0132 (2)	0.0254 (3)	−0.00904 (19)	0.0047 (4)	−0.0035 (4)
Cl2	0.0141 (3)	0.0197 (3)	0.0270 (5)	0.00944 (19)	0.0015 (4)	0.0017 (4)
P1	0.0080 (4)	0.0101 (4)	0.0093 (4)	−0.0006 (3)	−0.0014 (3)	0.0011 (3)
P2	0.0069 (4)	0.0120 (4)	0.0094 (4)	−0.0003 (3)	0.0010 (3)	−0.0030 (3)
O1	0.0152 (11)	0.0113 (8)	0.0173 (9)	−0.0001 (7)	−0.0042 (8)	−0.0031 (8)
O2	0.0177 (11)	0.0114 (9)	0.0177 (10)	−0.0031 (8)	0.0078 (8)	−0.0008 (7)
O3	0.0132 (12)	0.0214 (12)	0.0121 (10)	−0.0007 (9)	0.0022 (9)	0.0014 (8)
O4	0.0399 (18)	0.0200 (12)	0.0164 (11)	−0.0110 (10)	−0.0123 (11)	0.0038 (9)
O5	0.0134 (7)	0.0115 (6)	0.0228 (8)	0.0020 (6)	−0.0036 (12)	−0.0010 (11)
O11	0.0076 (12)	0.0166 (11)	0.0104 (10)	0.0031 (9)	0.0000 (9)	0.0010 (8)
O12	0.0113 (12)	0.0103 (10)	0.0106 (10)	−0.0006 (9)	−0.0046 (9)	−0.0009 (8)
O13	0.0080 (11)	0.0181 (11)	0.0141 (11)	−0.0013 (8)	−0.0033 (8)	0.0075 (8)
O21	0.0100 (13)	0.0240 (12)	0.0106 (11)	0.0036 (10)	0.0009 (9)	0.0004 (9)
O23	0.0102 (12)	0.0193 (11)	0.0164 (11)	−0.0053 (9)	0.0049 (8)	−0.0097 (9)
O22	0.0099 (12)	0.0107 (10)	0.0119 (10)	0.0003 (8)	0.0018 (9)	−0.0016 (8)
C1	0.0077 (10)	0.0089 (9)	0.0145 (12)	−0.0003 (7)	0.0007 (14)	0.0025 (12)

Geometric parameters (Å, º)

Sr—O21	2.499 (2)	P2—O23	1.566 (2)
Sr—O11	2.500 (2)	P2—C1	1.856 (4)
Sr—O4	2.524 (2)	O1—H1A	0.8500
Sr—O5	2.542 (1)	O1—H1B	0.8500
Sr—O3	2.552 (2)	O2—H2A	0.8500
Sr—O2	2.576 (2)	O2—H2B	0.8500
Sr—O1	2.609 (2)	O3—H3A	0.8500
Cl1—C1	1.800 (2)	O3—H3B	0.8500
Cl2—C1	1.784 (2)	O4—H4A	0.8500
P1—O11	1.495 (3)	O4—H4B	0.8500
P1—O12	1.503 (3)	O5—H5A	0.8500
P1—O13	1.568 (2)	O5—H5B	0.8501
P1—C1	1.849 (4)	O13—H13	0.9378
P2—O21	1.484 (2)	O23—H23	0.8504
P2—O22	1.499 (3)
O21—Sr—O11	77.69 (5)	O22—P2—O23	111.5 (1)
O21—Sr—O4	85.34 (8)	O21—P2—C1	107.0 (1)
O11—Sr—O4	127.53 (8)	O22—P2—C1	106.8 (1)
O21—Sr—O5	79.08 (7)	O23—P2—C1	103.7 (1)
O11—Sr—O5	77.56 (7)	Sr—O1—H1A	119.5
O4—Sr—O5	146.73 (8)	Sr—O1—H1B	98.5
O21—Sr—O3	122.32 (8)	H1A—O1—H1B	107.7
O11—Sr—O3	76.49 (8)	Sr—O2—H2A	110.2
O4—Sr—O3	71.75 (7)	Sr—O2—H2B	124.5
O5—Sr—O3	141.03 (8)	H2A—O2—H2B	107.7
O21—Sr—O2	156.60 (7)	Sr—O3—H3A	129.1
O11—Sr—O2	102.24 (7)	Sr—O3—H3B	104.1
O4—Sr—O2	111.51 (8)	H3A—O3—H3B	107.7
O5—Sr—O2	78.09 (6)	Sr—O4—H4A	125.8
O3—Sr—O2	79.60 (7)	Sr—O4—H4B	125.7
O21—Sr—O1	90.88 (7)	H4A—O4—H4B	107.7
O11—Sr—O1	151.57 (7)	Sr—O5—H5A	125.8
O4—Sr—O1	76.33 (7)	Sr—O5—H5B	118.2
O5—Sr—O1	74.73 (6)	H5A—O5—H5B	107.7
O3—Sr—O1	130.53 (7)	P1—O11—Sr	140.2 (1)
O2—Sr—O1	78.19 (7)	P1—O13—H13	103.5
O11—P1—O12	116.7 (1)	P2—O21—Sr	140.0 (1)
O11—P1—O13	109.1 (1)	P2—O23—H23	128.7
O12—P1—O13	111.5 (1)	Cl2—C1—Cl1	109.3 (1)
O11—P1—C1	106.8 (1)	Cl2—C1—P1	108.6 (2)
O12—P1—C1	107.6 (1)	Cl1—C1—P1	107.4 (2)
O13—P1—C1	104.3 (1)	Cl2—C1—P2	108.6 (2)
O21—P2—O22	118.0 (1)	Cl1—C1—P2	106.9 (2)
O21—P2—O23	108.7 (1)	P1—C1—P2	115.9 (1)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1A···O13^i	0.85	2.03	2.865 (3)	168
O1—H1B···O22^ii	0.85	2.03	2.773 (3)	145
O2—H2A···O12^ii	0.85	1.97	2.755 (3)	153
O2—H2B···O23^iii	0.85	2.02	2.841 (3)	162
O3—H3A···O21^iii	0.85	2.01	2.793 (3)	152
O3—H3B···O1^iii	0.85	2.10	2.890 (3)	155
O4—H4B···Cl1^iv	0.85	2.72	3.554 (3)	167
O4—H4A···O11^i	0.85	1.93	2.768 (3)	167
O5—H5A···O2^v	0.85	2.11	2.955 (3)	171
O5—H5B···O12^ii	0.85	2.29	2.987 (3)	139
O13—H13···O22^vi	0.94	1.68	2.558 (4)	154
O23—H23···O12^vii	0.85	1.73	2.546 (3)	161

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