Crystal structure of bis­[(1-ammonio-1-phosphono­eth­yl)phospho­nato]tetra­aqua­cadmium dihydrate: a powder X-ray diffraction study

In the compound [CdL₂(H₂O)₄]·2H₂O [L = (1-ammonio-1-phosphono­eth­yl)phospho­nate, C₂H₈NO₆P₂⁻], the Cd^II ion is situated on an inversion centre being coordinated by four aqua mol­ecules in the equatorial plane and two deprotonated phospho­nate O atoms from two L ligands in the axial positions in a distorted octa­hedral geometry. Each ligand L exists in a zwitterionic form, and with an intra­molecular O—H...O inter­action forming an S(6) ring motif and two intra­molecular N—H...O inter­actions each generating an S(5) ring motif. In the crystal, N—H...O and O—H...O hydrogen bonds link complex mol­ecules into a three-dimensional network with voids of 38 ų filled with ordered lattice water mol­ecules, which are also involved in O—H...O hydrogen bonding.

Key indicators

• Powder X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.012 Å
• R factor = 0.000
• wR factor = 0.000
• Data-to-parameter ratio = 0.0

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT342_ALERT_3_C Low Bond Precision on  C-C Bonds ...............     0.0120 Ang.

Alert level G
PLAT007_ALERT_5_G Number of Unrefined Donor-H Atoms ..............         11 Report
PLAT142_ALERT_4_G su on b - Axis Small or Missing ................    0.00005 Ang.
PLAT720_ALERT_4_G Number of Unusual/Non-Standard Labels ..........          9 Note
PLAT793_ALERT_4_G The Model has Chirality at P1      (Centro SPGR)          S Verify
PLAT793_ALERT_4_G The Model has Chirality at C1      (Centro SPGR)          S Verify
PLAT794_ALERT_5_G Tentative Bond Valency for Cd1     (II)    .....       2.54 Note
PLAT860_ALERT_3_G Number of Least-Squares Restraints .............          4 Note
PLAT981_ALERT_1_G No non-zero f" Anomalous Scattering Values Found     Please Check
PLAT986_ALERT_1_G No non-zero f' Anomalous Scattering Values Found     Please Check

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   1 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   9 ALERT level G = General information/check it is not something unexpected

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

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Computing details

Data collection: WinXPOW (Stoe & Cie, 1999); cell refinement: GSAS (Larson & Von Dreele, 2004); data reduction: WinXPOW (Stoe & Cie, 1999); program(s) used to solve structure: EXPO2014 (Altomare et al., 2013); program(s) used to refine structure: GSAS (Larson & Von Dreele, 2004); molecular graphics: Mercury (Macrae et al., 2006); software used to prepare material for publication: publCIF (Westrip, 2010).

Bis[(1-ammonio-1-phosphonoethyl)phosphonato]tetraaquacadmium dihydrate

Crystal data

[Cd(C2H8NO6P2)2(H2O)4]·2H2O	Z = 2
Mr = 628.57	F(000) = 636
Monoclinic, P21/c	Dx = 2.048 Mg m^−3
Hall symbol: -P 2ybc	Cu Kα1 radiation, λ = 1.5406 Å
a = 10.69424 (12) Å	µ = 12.41 mm^−1
b = 5.61453 (5) Å	T = 298 K
c = 17.2737 (2) Å	Particle morphology: fine powder
β = 100.7029 (8)°	white
V = 1019.12 (2) Å^3	flat_sheet, 8 × 8 mm

Data collection

Stoe transmission STADI-P diffractometer	Scan method: step
Radiation source: sealed X-ray tube	Absorption correction: for a cylinder mounted on the φ axis [GSAS (Larson & Von Dreele, 2004) absorption/surface roughness correction: function No. 4, flat-plate transmission absorption correction, terms = 0.75850]
Ge 111 monochromator	Tmin = 0.195, Tmax = 0.310
Specimen mounting: Powder loaded into two Mylar foils	2θmin = 6.00°, 2θmax = 89.98°, 2θstep = 0.02°
Data collection mode: transmission

Refinement

Refinement on Inet	Profile function: CW Profile function number 4 with 21 terms Pseudovoigt profile coefficients as parameterized in (Thompson et al., 1987). Asymmetry correction of (Finger et al., 1994). Microstrain broadening by (Stephens, 1999). #1(GU) = 0.000 #2(GV) = 0.000 #3(GW) = 7.136 #4(GP) = 0.000 #5(LX) = 2.421 #6(ptec) = 0.11 #7(trns) = 0.00 #8(shft) = 0.0000 #9(sfec) = 0.00 #10(S/L) = 0.0225 #11(H/L) = 0.0225 #12(eta) = 0.6026 #13(S400 ) = 1.2E-02 #14(S040 ) = 1.0E-01 #15(S004 ) = 1.2E-03 #16(S220 ) = 3.3E-02 #17(S202 ) = 6.7E-03 #18(S022 ) = 1.7E-02 #19(S301 ) = 1.1E-02 #20(S103 ) = 2.3E-03 #21(S121 ) = 1.5E-02 Peak tails are ignored where the intensity is below 0.0010 times the peak Aniso. broadening axis 0.0 0.0 1.0
Least-squares matrix: full	133 parameters
Rp = 0.029	4 restraints
Rwp = 0.039	H-atom parameters not refined
Rexp = 0.025	Weighting scheme based on measured s.u.'s
R(F^2) = 0.04534	(Δ/σ)max = 0.03
4100 data points	Background function: GSAS Background function number 1 with 20 terms. Shifted Chebyshev function of 1st kind 1: 1216.00 2: -1325.95 3: 695.908 4: -224.478 5: 51.5854 6: -12.9254 7: 7.98937 8: -13.4593 9: 4.35490 10: 32.6578 11: -32.8988 12: -6.52632 13: -18.8133 14: 23.4504 15: -2.70081 16: -0.874623 17: -28.0163 18: 27.3423 19: 2.28961 20: -11.2631

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

	x	y	z	Uiso*/Ueq
C1	0.1555 (5)	0.3764 (12)	0.6381 (5)	0.015*
C2	0.2285 (11)	0.4133 (17)	0.7222 (5)	0.015*
H2a	0.17609	0.50488	0.75213	0.02*
H2b	0.3063	0.50177	0.72104	0.02*
H2c	0.24919	0.26144	0.74755	0.02*
N1	0.1274 (11)	0.6170 (16)	0.6028 (7)	0.02*
H1na	0.07228	0.68814	0.62561	0.025*
H1nb	0.09382	0.59823	0.55236	0.025*
H1nc	0.19624	0.69829	0.60678	0.025*
P1	0.2594 (5)	0.2361 (7)	0.5774 (3)	0.01*
O1	0.1897 (8)	0.2047 (13)	0.4907 (6)	0.01*
H1	0.11151	0.1887	0.48952	0.015*
O2	0.3659 (9)	0.4155 (15)	0.5771 (6)	0.01*
O3	0.3024 (8)	−0.0094 (16)	0.6124 (6)	0.01*
P2	0.0019 (4)	0.2252 (6)	0.6342 (3)	0.01*
O4	−0.0728 (9)	0.1904 (14)	0.5539 (6)	0.01*
O5	−0.0807 (8)	0.4058 (11)	0.6745 (5)	0.01*
H5	−0.06622	0.38276	0.7235	0.03*
O6	0.0255 (7)	−0.0022 (16)	0.6785 (5)	0.01*
Cd1	0.5	0.5	0.5	0.0093 (7)*
O1W	0.5302 (11)	0.8211 (15)	0.5815 (7)	0.029 (4)*
H1W1	0.56	0.91732	0.55443	0.03*
H2W1	0.47216	0.89419	0.59649	0.03*
O2W	0.6537 (10)	0.2995 (14)	0.5866 (6)	0.020 (3)*
H1W2	0.63758	0.22791	0.62489	0.03*
H2W2	0.72024	0.23865	0.57871	0.03*
O3w	0.5739 (11)	0.3949 (14)	0.7310 (6)	0.028 (3)*
H1W3	0.54032	0.26314	0.72841	0.03*
H2W3	0.5752	0.43812	0.77663	0.03*

Geometric parameters (Å, º)

C1—C2	1.530 (12)	P2—O5	1.588 (7)
C1—N1	1.490 (12)	P2—O6	1.486 (9)
C1—P1	1.840 (9)	O5—H5	0.842
C1—P2	1.839 (7)	Cd1—O2	2.183 (8)
C2—H2a	0.976	Cd1—O2^i	2.183 (8)
C2—H2b	0.972	Cd1—O1W	2.274 (9)
C2—H2c	0.965	Cd1—O1W^i	2.274 (9)
N1—H1na	0.865	Cd1—O2W	2.300 (10)
N1—H1nb	0.885	Cd1—O2W^i	2.300 (10)
N1—H1nc	0.858	O1W—H1W1	0.817
P1—O1	1.555 (11)	O1W—H2W1	0.824
P1—O2	1.521 (9)	O2W—H1W2	0.820
P1—O3	1.541 (9)	O2W—H2W2	0.823
O1—H1	0.838	O3w—H1W3	0.820
P2—O4	1.480 (10)	O3w—H2W3	0.823
C2—C1—N1	107.2 (7)	C1—P2—O6	108.2 (5)
C2—C1—P1	110.1 (6)	O4—P2—O5	104.3 (5)
C2—C1—P2	113.1 (7)	O4—P2—O6	112.3 (6)
N1—C1—P1	104.6 (5)	O5—P2—O6	112.2 (5)
N1—C1—P2	107.0 (6)	P2—O5—H5	109.2
P1—C1—P2	114.3 (4)	O2—Cd1—O2^i	180.0
C1—C2—H2a	109.4	O2—Cd1—O1W	80.1 (4)
C1—C2—H2b	109.6	O2—Cd1—O1W^i	99.9 (4)
C1—C2—H2c	110.1	O2—Cd1—O2W	88.2 (3)
H2a—C2—H2b	108.6	O2—Cd1—O2W^i	91.8 (3)
H2a—C2—H2c	109.4	O2^i—Cd1—O1W	99.9 (4)
H2b—C2—H2c	109.7	O2^i—Cd1—O1W^i	80.1 (4)
C1—N1—H1na	109.5	O2^i—Cd1—O2W	91.8 (3)
C1—N1—H1nb	108.0	O2^i—Cd1—O2W^i	88.2 (3)
C1—N1—H1nc	110.1	O1W—Cd1—O1W^i	180.0
H1na—N1—H1nb	108.5	O1W—Cd1—O2W	89.0 (4)
H1na—N1—H1nc	111.4	O1W—Cd1—O2W^i	91.0 (4)
H1nb—N1—H1nc	109.1	O1W^i—Cd1—O2W	91.0 (4)
C1—P1—O1	111.5 (6)	O1W^i—Cd1—O2W^i	89.0 (4)
C1—P1—O2	104.5 (5)	O2W—Cd1—O2W^i	180.0
C1—P1—O3	109.1 (4)	Cd1—O1W—H1W1	101.2
O1—P1—O2	107.2 (5)	Cd1—O1W—H2W1	124.1
O1—P1—O3	109.4 (5)	H1W1—O1W—H2W1	104.3
O2—P1—O3	115.1 (6)	Cd1—O2W—H1W2	122.2
P1—O1—H1	109.4	Cd1—O2W—H2W2	129.1
P1—O2—Cd1	136.4 (6)	H1W2—O2W—H2W2	104.3
C1—P2—O4	114.8 (5)	H1W3—O3w—H2W3	104.3
C1—P2—O5	104.8 (4)
O1W—Cd1—O2—P1	168.8 (9)	O1—P1—C1—C2	−177.9 (6)
O2W—Cd1—O2—P1	−101.9 (8)	O2—P1—C1—C2	−62.3 (7)
O1W^i—Cd1—O2—P1	−11.2 (9)	O3—P1—C1—C2	61.3 (7)
O2W^i—Cd1—O2—P1	78.1 (8)	O4—P2—C1—P1	−54.2 (6)
O3—P1—O2—Cd1	84.9 (9)	O5—P2—C1—P1	−168.0 (5)
C1—P1—O2—Cd1	−155.4 (7)	O6—P2—C1—P1	72.1 (6)
O1—P1—O2—Cd1	−37.0 (9)	O4—P2—C1—N1	61.1 (8)
O1—P1—C1—P2	53.6 (6)	O5—P2—C1—N1	−52.7 (8)
O2—P1—C1—P2	169.2 (5)	O6—P2—C1—N1	−172.6 (7)
O3—P1—C1—P2	−67.2 (6)	O4—P2—C1—C2	178.9 (6)
O1—P1—C1—N1	−63.1 (7)	O5—P2—C1—C2	65.0 (7)
O2—P1—C1—N1	52.5 (8)	O6—P2—C1—C2	−54.9 (7)
O3—P1—C1—N1	176.1 (7)

Symmetry code: (i) −x+1, −y+1, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···O4	0.84	2.44	3.196 (13)	151
O1—H1···O4^ii	0.84	2.27	2.592 (12)	103
N1—H1NA···O5	0.87	2.53	2.986 (14)	114
N1—H1NA···O6^iii	0.87	2.07	2.828 (13)	146
N1—H1NB···O4^iv	0.88	2.16	2.872 (15)	137
N1—H1NC···O2	0.86	2.53	2.899 (15)	107
N1—H1NC···O3^iii	0.86	1.99	2.796 (14)	156
O1W—H1W1···O2W^iii	0.82	2.39	2.987 (13)	131
O5—H5···O6^v	0.84	1.79	2.551 (12)	150
O1W—H2W1···O3^iii	0.82	1.96	2.758 (15)	162
O2W—H1W2···O3W	0.82	2.27	2.833 (15)	126
O2W—H2W2···O4^vi	0.82	2.35	3.141 (15)	162
O3W—H1W3···O3W^vii	0.82	2.56	3.346 (13)	160
O3W—H2W3···O3^viii	0.82	2.13	2.833 (14)	143

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