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Alendronate is used clinically in the treatment of skeletal disorders, the mode of action depending on the adsorption to calcium hydroxy­apatite crystals (bone). In the title compound, calcium 4-ammonium-1-hydroxy­butyl­idene-1,1-bis­phospho­n­ate, Ca2+·2C4H12NO7P2-, alendronate is a zwitterion, possessing one negative charge on each PO3 group and a protonated N atom. The zwitterion is disposed with its negative end facing the Ca2+ ion, while its positive end is stretched in the opposite direction. The geometry of the carbon chain is all-trans, while the hydroxy group is approximately gauche. The Ca2+ ion lies on a twofold axis parallel to b. The coordination sphere around the metal cation is octahedral and is determined by monodentate- and bidentate-coordinated alendronate zwitterions. The O...O bite distance is 3.080 (2) Å. Coordinated Ca2+ metal cations are arranged at the centre of a column running along c.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270103025599/sq1139sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270103025599/sq1139Isup2.hkl
Contains datablock I

CCDC reference: 229082

Comment top

Bisphosphonates are a class of compounds in which the P–C–P bridge replaces the P–O–P group of naturally occurring pyrophosphate. Such a characteristic confers on bisphosphonates the capacity to interact avidly with the mineral phase of bone tissue (calcium hydroxyapatite crystals; Compston, 1994; Martin & Grill, 2000). Bisphosphonates containing an N atom in their structure, including alendronate, are potent inhibitors of osteoclast-mediated bone resorption (Shinkai & Ohta, 1996; Widler et al., 2002). At sites of bone resorption, the compound is taken up by osteoclasts, which undergo a series of intracellular events (e.g. inhibition of the enzymes in the mevalonate pathway) that finally lead to their loss of activity and death by apoptosis (Beek et al., 2002). Clinical uses of alendronate include the treatment of bone disorders, such as osteoporosis and Paget's disease (Dyer, 2003).

Interest in studying the title compound comes from the fact that, despite their biomedical importance, only a few structures of calcium salts of bisphosphonates are known. The first crystal structures determined correspond to those of etidronate [calcium dihydrogen ethane-1-hydroxy-1,1-diphosphonate dihydrate; CSD (Allen, 2002) refcode CAEHDP; Uchtman, 1972] and clodronate (calcium dichloromethylene-1,1-diphosphonate pentahydrate; CAVKUF; Nardelli et al., 1983), while for the more potent amino–bisphosphonates, the structure of pamidronate (calcium 3-ammonium-1-hydroxypropylidene-1,1-bisphosphonate monohydrate; XUGGEL; Fernández et al., 2002) has only recently been described. In the latter work, the structures of the free acid and of the monovalent (Na+) and divalent (Ca2+) metal cation salts of pamidronate were studied and their features were compared. Using structural data from the free acid (4-ammonium-1-hydroxybutylidene-1,1-bisphosphonic acid; GOWZEX; Ohanessian et al., 1997), the monosodium salt of alendronate (4-ammonium-1-hydroxybutylidene-1,1-bisphosphonate trihydrate; TEHWOS; Vega et al., 1996) and the Ca2+ salt, (I), a similar study was carried out, the results of which are reported here.

The structure of the molecular anion in (I), hereafter CaH2ALN, is composed of the P1—C1—P2 bridge, a hydroxy group and an alkylamine side chain attached to the geminal C atom (C1; Fig. 1). Like the previously studied free acid, H3ALN (Ohanessian et al., 1997), and the trihydrated sodium salt, NaH2ALN (Vega et al., 1996), (I) has zwitterionic character, with atom N1 bearing the positive charge. In their salts, the overall charge of the zwitterions is −1, so alendronate forms 1:1 and 2:1 complexes with Na+ and Ca2+ ions, respectively. The geometry around the P atoms is tetrahedral (Table 1), and the lengths of the P—O bonds are close to 1.51 and 1.57 Å for the P—O(unprotonated) and P—O(protonated) distances, respectively. In each PO3 group, the largest bond angle is that between the pair of unprotonated O atoms. The P—C bond distances and the P—C—P bond angle are in good agreement with the values found in H3ALN [1.847 (4) and 1839 (4) Å, and 113.5 (2)°] and NaH2ALN [1.860 (3) and 1.854 (3) Å, and 110.0 (1)°].

Viewed along the P···P vector, the mutual orientation of the PO3 groups defines a planar `W'-like arrangement of the O2—P1—C1—P2—O6 chain. The relevant torsion angles are 170.7 (2) and −169.2 (2), 154.04 (12) and 156.04 (12), and −162.74 (10) and −170.15 (10)° for H3ALN, NaH2ALN and CaH2ALN, respectively. The sp3-hybridized C2 atom has a distorted tetrahedral geometry, as indicated by the value of the C1—C2—C3 bond angle [117.7 (2)°]. An explanation for this distortion can be found when considering the intramolecular interactions in which these atoms are involved, where the H···O distance is less than the sum of the van der Waals radii [H4···O6 = 2.479 Å, H7···O2 = 2.534 Å, and H6···O7 = 2.693 Å]. The same geometry was observed for atom C2 in H3ALN and NaH2ALN, the C1—C2—C3 bond angles being 116.6 (3) and 113.9 (2)°, respectively. Also, the disposition of the C2—C3 bond is similar in the three structures, the values of the P1—C1—C2—C3 and P2—C1—C2—C3 torsion angles being 60.5 (6) and −174.5 (4), 57.3 (3) and −179.5 (2), and −67.3 (2) and 169.04 (16)°, for H3ALN, NaH2ALN and CaH2ALN, respectively.

For the related compound pamidronate (3-ammonium-1-hydroxypropylidene-1,1-bisphosphonate), the comparison of the structures of the free acid, the monovalent (Na+) salt and the divalent (Ca2+) salt reveals a different conformation of the carbon chain in the Ca2+ complex (Fernández et al., 2002). In this structure, the conformation of the C—C—C—N chain is close to gauche, as shown by the value of the torsion angle [−72.1 (2)°], while in the free acid [−168.9 (2)°] and the disodium salt [153.6 (3)°], the conformation is trans. The hydroxy group is gauche in the calcium salt of pamidronate, which enables the formation of the intramolecular NH···O(hydroxy) hydrogen bond [D···A = 2.692 (2) Å, H···A = 1.93 (4) Å and D—H···A = 132 (3)°]. For alendronate, the comparison of the geometrical data among the structures of H3ALN, NaH2ALN and CaH2ALN gave no dissimilarities. In each, the conformation of the C—C—C—C—N backbone is all-trans, while the hydroxy group is gauche. For (I), the relevant torsion angles are 52.6 (2) [O7—C1—C2—C3], 178.61 (18) [C1—C2—C3—C4] and 170.91 (17)° [C2–C3–C4–N1].

The Ca2+ ion lies on a twofold axis parallel to b. The environment around the Ca2+ ion (Fig. 2) is a somewhat distorted octahedron and consists of three symmetry-independent bonds provided by one monodentate and one bidentate chelator. The Ca2+ ion is situated on a local pseudo-mirror plane, which is defined by atoms O3(-x + 1, y, −z + 1), O3(x, −y, z + 1/2), O5 and O5(-x + 1, y, −z + 3/2) [the r.m.s. deviation from the least-squares mean plane of the fitted atoms is 0.146 (s.u. value?)Å]. Apical atoms O1 and O1(-x + 1, y, −z + 3/2) are 2.283 (2) Å above and below this plane, forming an O1···Ca···O1(-x + 1, y, −z + 3/2) angle of 160.02 (12)°. The Ca···O contact distances range from 2.3037 (15) to 2.3444 (15) Å (Table 1). The bite O1···O5 distance is 3.080 (2) Å, well within the range found for the O atoms in crystals of calcium hydroxyapatite, which are bound more tightly to the Ca2+ ion (Nardelli et al., 1983), thus explaining the biological activity of the compound (which compound?). The remaining phosphonyl O atoms, namely the deprotonated atom O6, and the protonated atoms O2 and O4, are not coordinated, and there are no other contacts below 3.2 Å to indicate additional coordination to the Ca2+ ion. Hydroxy atom O7 is separated by ca 4 Å from the metal cation, and hence the zwitterion cannot function as a tridentate ligand. This coordination is the main difference observed between the zwitterions in their Na+ and Ca2+ salts, since NaH2ALN uses two phosphonyl O atoms and the hydroxy O atom to coordinate as a tridentate ligand (Vega et al., 1996). The same trend was observed for etidronate and pamidronate (Fernández et al., 2002).

The Ca2+ ions are arranged in a columnar fashion along c (Fig. 2). As expected, the negatively charged part of the zwitterion is directed towards the cations close to the centre of the column, while its positive end is stretched, ?in the oppostite direction, to its maximum length. Zwitterions inside the column are hydrogen bonded via O—H···O interactions (Table 2), while N—H···O interactions occur between adjacent columns.

Experimental top

A sample of monosodium alendronate trihydrate was obtained from LABORATORIOS GADOR SA, Buenos Aires, Argentina. The calcium salt was prepared as described by Uchtman (1972). A powdered sample of the bisphosphonate (Mw 325.12) was added to Ca(NO3)2·4H2O (Mw 236.15, Fluka, Switzerland) and then placed in an excess of water. Crystals suitable for X-ray diffraction were obtained by evaporating this solution in an oven at 315 K.

Refinement top

H atoms attached to C atoms were placed 0.97 Å from their hosts and refined using a riding model, while their isotropic displacement parameters were constrained to 1.2Ueq of their carrier atoms. The positional parameters of the H atoms attached to atom N1 were freely refined, while for H atoms bonded to O atoms, the O–H distance was restrained to 0.85 (3) Å using the DFIX command in SHELXL97 (Sheldrick, 1997). The displacement parameters of these H atoms were set to 1.5Ueq of their carrier atoms.

Computing details top

Data collection: SMART-NT (Bruker, 1998); cell refinement: SMART-NT; data reduction: SAINT-NT (Bruker, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ZORTEP (Zsolnai & Pritzkow, 1995); software used to prepare material for publication: PARST (Nardelli, 1995) and WinGX (Farrugia, 1999).

Figures top
[Figure 1] Fig. 1. : A view of (I), with the atom-numbering scheme and displacement ellipsoids drawn at the 50% probability level.
[Figure 2] Fig. 2. : A simplified packing diagram, showing the calcium coordination sphere (dashed lines). Only H atoms attached to non-C carriers are shown. [Symmetry codes: (i) −x + 1, −y, −z + 1, (ii) −x + 1, y, −z + 3/2 and (iii) x, −y, z + 1/2, respectively.]
(I) top
Crystal data top
Ca2+·2C4H12NO7P2F(000) = 1112
Mr = 536.26Dx = 1.891 Mg m3
Monoclinic, C2/cMelting point: 507 K
Hall symbol: -C 2ycMo Kα radiation, λ = 0.71073 Å
a = 15.9236 (7) ÅCell parameters from 971 reflections
b = 12.4044 (6) Åθ = 3.9–26.0°
c = 11.4378 (5) ŵ = 0.75 mm1
β = 123.516 (2)°T = 120 K
V = 1883.59 (15) Å3Prism, colorless
Z = 40.26 × 0.1 × 0.06 mm
Data collection top
Bruker SMART-6000 CCD DiffractometerRint = 0.092
ω scansθmax = 28.3°, θmin = 2.3°
10660 measured reflectionsh = 2121
2342 independent reflectionsk = 1616
2172 reflections with I > 2σ(I)l = 1415
Refinement top
Refinement on F23 restraints
Least-squares matrix: fullH atoms treated by a mixture of independent and constrained refinement
R[F2 > 2σ(F2)] = 0.036 w = 1/[σ2(Fo2) + (0.0227P)2 + 3.8283P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.094(Δ/σ)max = 0.002
S = 1.22Δρmax = 0.69 e Å3
2342 reflectionsΔρmin = 0.41 e Å3
150 parameters
Crystal data top
Ca2+·2C4H12NO7P2V = 1883.59 (15) Å3
Mr = 536.26Z = 4
Monoclinic, C2/cMo Kα radiation
a = 15.9236 (7) ŵ = 0.75 mm1
b = 12.4044 (6) ÅT = 120 K
c = 11.4378 (5) Å0.26 × 0.1 × 0.06 mm
β = 123.516 (2)°
Data collection top
Bruker SMART-6000 CCD Diffractometer2172 reflections with I > 2σ(I)
10660 measured reflectionsRint = 0.092
2342 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0363 restraints
wR(F2) = 0.094H atoms treated by a mixture of independent and constrained refinement
S = 1.22Δρmax = 0.69 e Å3
2342 reflectionsΔρmin = 0.41 e Å3
150 parameters
Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
C10.54392 (14)0.25618 (16)0.5572 (2)0.0098 (4)
C20.54499 (15)0.34024 (17)0.4600 (2)0.0121 (4)
H40.4960.39540.44180.014*
H50.5220.30540.37130.014*
C30.64553 (15)0.39656 (18)0.5102 (2)0.0149 (4)
H60.66890.43620.59610.018*
H70.69630.34380.52830.018*
C40.62697 (15)0.47291 (16)0.3948 (2)0.0120 (4)
H80.61310.43140.31410.014*
H90.56820.51680.36640.014*
N10.71552 (14)0.54470 (15)0.4416 (2)0.0126 (4)
H100.773 (2)0.502 (2)0.488 (3)0.019*
H110.719 (2)0.593 (2)0.506 (3)0.019*
H120.705 (2)0.585 (2)0.371 (3)0.019*
O10.60021 (10)0.05395 (11)0.66310 (15)0.0111 (3)
O20.73184 (10)0.16826 (12)0.66120 (16)0.0110 (3)
H20.758 (2)0.174 (2)0.749 (2)0.017*
O30.59420 (10)0.09197 (12)0.43869 (16)0.0120 (3)
O40.37078 (11)0.14759 (12)0.35534 (16)0.0128 (3)
H30.389 (2)0.0848 (19)0.365 (3)0.019*
O50.40754 (10)0.16621 (12)0.60275 (16)0.0120 (3)
O60.34660 (10)0.32321 (11)0.43060 (16)0.0111 (3)
O70.58685 (11)0.30474 (12)0.69445 (16)0.0121 (3)
H10.580 (2)0.258 (2)0.744 (3)0.018*
P10.61831 (4)0.13384 (4)0.57788 (6)0.00802 (13)
P20.40982 (4)0.22187 (4)0.48696 (5)0.00784 (13)
Ca0.50.02131 (4)0.750.00837 (14)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0101 (8)0.0087 (8)0.0109 (10)0.0004 (7)0.0060 (7)0.0010 (7)
C20.0123 (9)0.0130 (9)0.0110 (10)0.0006 (7)0.0065 (8)0.0016 (8)
C30.0123 (9)0.0145 (10)0.0174 (11)0.0004 (8)0.0079 (8)0.0038 (8)
C40.0083 (8)0.0115 (9)0.0149 (10)0.0022 (7)0.0056 (8)0.0015 (7)
N10.0128 (8)0.0111 (8)0.0151 (9)0.0014 (7)0.0084 (7)0.0016 (7)
O10.0119 (6)0.0097 (6)0.0133 (7)0.0008 (5)0.0080 (6)0.0008 (6)
O20.0078 (6)0.0142 (7)0.0092 (7)0.0014 (5)0.0036 (6)0.0020 (6)
O30.0110 (6)0.0141 (7)0.0105 (7)0.0016 (5)0.0056 (6)0.0023 (6)
O40.0148 (7)0.0091 (7)0.0102 (7)0.0017 (5)0.0041 (6)0.0021 (5)
O50.0100 (6)0.0137 (7)0.0123 (7)0.0012 (5)0.0062 (6)0.0023 (6)
O60.0101 (6)0.0109 (7)0.0106 (7)0.0022 (5)0.0047 (6)0.0010 (5)
O70.0154 (7)0.0116 (7)0.0102 (7)0.0025 (6)0.0076 (6)0.0024 (6)
P10.0068 (2)0.0076 (2)0.0089 (3)0.00032 (17)0.00385 (19)0.00065 (17)
P20.0068 (2)0.0077 (2)0.0080 (3)0.00051 (17)0.00346 (19)0.00030 (17)
Ca0.0079 (2)0.0095 (3)0.0065 (3)00.0032 (2)0
Geometric parameters (Å, º) top
C1—O71.453 (2)O1—P11.5250 (15)
C1—C21.531 (3)O2—P11.5672 (14)
C1—P11.858 (2)O2—H20.85 (2)
C1—P21.869 (2)O3—P11.5089 (16)
C2—C31.538 (3)O3—Cai2.3037 (15)
C2—H40.97O4—P21.5710 (16)
C2—H50.97O4—H30.82 (2)
C3—C41.516 (3)O5—P21.5116 (16)
C3—H60.97O6—P21.5141 (15)
C3—H70.97O7—H10.86 (2)
C4—N11.495 (3)Ca—O12.3344 (15)
C4—H80.97Ca—O52.3444 (15)
C4—H90.97Ca—O3i2.3037 (15)
N1—H100.93 (3)Ca—O3ii2.3037 (15)
N1—H110.92 (3)Ca—O1iii2.3344 (15)
N1—H120.88 (3)Ca—O5iii2.3444 (15)
O7—C1—C2108.36 (16)P1—O3—Cai148.55 (9)
O7—C1—P1108.33 (13)P2—O4—H3121 (2)
C2—C1—P1112.77 (14)P2—O5—Ca132.08 (9)
O7—C1—P2107.64 (13)C1—O7—H1106 (2)
C2—C1—P2108.14 (13)O3—P1—O1115.02 (9)
P1—C1—P2111.44 (10)O3—P1—O2105.75 (8)
C1—C2—C3117.70 (17)O1—P1—O2110.49 (8)
C1—C2—H4107.9O3—P1—C1111.95 (9)
C3—C2—H4107.9O1—P1—C1106.26 (9)
C1—C2—H5107.9O2—P1—C1107.16 (9)
C3—C2—H5107.9O5—P2—O6114.85 (9)
H4—C2—H5107.2O5—P2—O4112.55 (9)
C4—C3—C2107.25 (17)O6—P2—O4105.11 (8)
C4—C3—H6110.3O5—P2—C1107.58 (9)
C2—C3—H6110.3O6—P2—C1109.10 (9)
C4—C3—H7110.3O4—P2—C1107.40 (9)
C2—C3—H7110.3O3i—Ca—O3ii104.83 (8)
H6—C3—H7108.5O3i—Ca—O187.22 (5)
N1—C4—C3111.63 (17)O3ii—Ca—O1105.08 (5)
N1—C4—H8109.3O3i—Ca—O1iii105.08 (5)
C3—C4—H8109.3O3ii—Ca—O1iii87.22 (5)
N1—C4—H9109.3O1—Ca—O1iii160.02 (7)
C3—C4—H9109.3O3i—Ca—O5iii165.10 (6)
H8—C4—H9108O3ii—Ca—O5iii88.22 (5)
C4—N1—H10107.7 (18)O1—Ca—O5iii82.37 (5)
C4—N1—H11107.0 (18)O1iii—Ca—O5iii82.35 (5)
H10—N1—H11108 (3)O3i—Ca—O588.22 (5)
C4—N1—H12110.0 (19)O3ii—Ca—O5165.10 (6)
H10—N1—H12118 (3)O1—Ca—O582.35 (5)
H11—N1—H12105 (3)O1iii—Ca—O582.37 (5)
P1—O1—Ca143.11 (9)O5iii—Ca—O579.89 (8)
P1—O2—H2113.2 (19)
O7—C1—C2—C352.6 (2)Ca—O5—P2—O467.80 (13)
P1—C1—C2—C367.3 (2)Ca—O5—P2—C150.31 (13)
P2—C1—C2—C3169.04 (16)O7—C1—P2—O546.57 (15)
C1—C2—C3—C4178.61 (18)C2—C1—P2—O5163.44 (14)
C2—C3—C4—N1170.91 (17)P1—C1—P2—O572.07 (12)
Cai—O3—P1—O129.0 (2)O7—C1—P2—O678.61 (14)
Cai—O3—P1—O2151.21 (16)C2—C1—P2—O638.26 (16)
Cai—O3—P1—C192.42 (18)P1—C1—P2—O6162.74 (10)
Ca—O1—P1—O3113.37 (14)O7—C1—P2—O4167.96 (12)
Ca—O1—P1—O2127.02 (14)C2—C1—P2—O475.17 (15)
Ca—O1—P1—C111.09 (17)P1—C1—P2—O449.31 (13)
O7—C1—P1—O3167.43 (12)P1—O1—Ca—O3i98.77 (15)
C2—C1—P1—O347.50 (16)P1—O1—Ca—O3ii156.62 (14)
P2—C1—P1—O374.34 (13)P1—O1—Ca—O5iii70.55 (15)
O7—C1—P1—O166.23 (14)P1—O1—Ca—O510.20 (14)
C2—C1—P1—O1173.84 (13)P2—O5—Ca—O3i74.11 (12)
P2—C1—P1—O152.00 (12)P2—O5—Ca—O3ii134.39 (18)
O7—C1—P1—O251.92 (15)P2—O5—Ca—O113.33 (11)
C2—C1—P1—O268.01 (15)P2—O5—Ca—O1iii179.58 (12)
P2—C1—P1—O2170.15 (10)P2—O5—Ca—O5iii96.88 (12)
Ca—O5—P2—O6171.98 (10)
Symmetry codes: (i) x+1, y, z+1; (ii) x, y, z+1/2; (iii) x+1, y, z+3/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H10···O3iv0.93 (3)2.13 (3)3.057 (2)170 (3)
N1—H11···O6v0.92 (3)1.88 (3)2.720 (2)150 (2)
N1—H12···O7vi0.88 (3)2.30 (3)3.046 (2)143 (2)
O7—H1···O5iii0.86 (2)2.01 (2)2.848 (2)167 (3)
O2—H2···O6vii0.85 (2)1.76 (2)2.574 (2)162 (3)
O4—H3···O1i0.82 (2)1.78 (2)2.572 (2)164 (3)
O7—H1···O50.86 (2)2.56 (3)2.983 (2)112 (2)
Symmetry codes: (i) x+1, y, z+1; (iii) x+1, y, z+3/2; (iv) x+3/2, y+1/2, z+1; (v) x+1, y+1, z+1; (vi) x, y+1, z1/2; (vii) x+1/2, y+1/2, z+1/2.

Experimental details

Crystal data
Chemical formulaCa2+·2C4H12NO7P2
Mr536.26
Crystal system, space groupMonoclinic, C2/c
Temperature (K)120
a, b, c (Å)15.9236 (7), 12.4044 (6), 11.4378 (5)
β (°) 123.516 (2)
V3)1883.59 (15)
Z4
Radiation typeMo Kα
µ (mm1)0.75
Crystal size (mm)0.26 × 0.1 × 0.06
Data collection
DiffractometerBruker SMART6000 CCD Diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
10660, 2342, 2172
Rint0.092
(sin θ/λ)max1)0.667
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.036, 0.094, 1.22
No. of reflections2342
No. of parameters150
No. of restraints3
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.69, 0.41

Computer programs: SMART-NT (Bruker, 1998), SMART-NT, SAINT-NT (Bruker, 1998), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ZORTEP (Zsolnai & Pritzkow, 1995), PARST (Nardelli, 1995) and WinGX (Farrugia, 1999).

Selected geometric parameters (Å, º) top
C1—P11.858 (2)O5—P21.5116 (16)
C1—P21.869 (2)O6—P21.5141 (15)
O1—P11.5250 (15)Ca—O12.3344 (15)
O2—P11.5672 (14)Ca—O52.3444 (15)
O3—P11.5089 (16)Ca—O3i2.3037 (15)
O4—P21.5710 (16)
O3—P1—O1115.02 (9)O5—P2—O6114.85 (9)
O3—P1—O2105.75 (8)O5—P2—O4112.55 (9)
O1—P1—O2110.49 (8)O6—P2—O4105.11 (8)
O3—P1—C1111.95 (9)O5—P2—C1107.58 (9)
O1—P1—C1106.26 (9)O6—P2—C1109.10 (9)
O2—P1—C1107.16 (9)O4—P2—C1107.40 (9)
P2—C1—P1—O374.34 (13)P1—C1—P2—O572.07 (12)
P2—C1—P1—O152.00 (12)P1—C1—P2—O6162.74 (10)
P2—C1—P1—O2170.15 (10)P1—C1—P2—O449.31 (13)
Symmetry code: (i) x+1, y, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H10···O3ii0.93 (3)2.13 (3)3.057 (2)170 (3)
N1—H11···O6iii0.92 (3)1.88 (3)2.720 (2)150 (2)
N1—H12···O7iv0.88 (3)2.30 (3)3.046 (2)143 (2)
O7—H1···O5v0.86 (2)2.01 (2)2.848 (2)167 (3)
O2—H2···O6vi0.85 (2)1.76 (2)2.574 (2)162 (3)
O4—H3···O1i0.82 (2)1.78 (2)2.572 (2)164 (3)
O7—H1···O50.86 (2)2.56 (3)2.983 (2)112 (2)
Symmetry codes: (i) x+1, y, z+1; (ii) x+3/2, y+1/2, z+1; (iii) x+1, y+1, z+1; (iv) x, y+1, z1/2; (v) x+1, y, z+3/2; (vi) x+1/2, y+1/2, z+1/2.
 

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