Poly­[[di­aqua(μ₄-squarato-O,O′,O′′,O′′′)­nickel(II)] 0.71-hydrate]

In the title compound, {[Ni(C₄O₄)(H₂O)₂]·0.71H₂O}_n, each Ni atom is coordinated by four squarate dianions and two water mol­ecules within a slightly distorted octahedron. The water mol­ecules occupy general positions and the Ni atom, as well as the two crystallographically independent squarate dianions, are located in special positions. Hydro­gen bonding is found between the O atoms of the squarate dianions and the water mol­ecules. In the crystal structure, voids are found that are filled with disordered clathrate water mol­ecules. The compound is isotypic with the previously reported Mn, Fe and Co compounds.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.003 Å
• Disorder in solvent or counterion
• R factor = 0.024
• wR factor = 0.077
• Data-to-parameter ratio = 11.9

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


 Alert Level C:



REFLT_03
         From the CIF: _diffrn_reflns_theta_max           26.50
         From the CIF: _reflns_number_total                704
         TEST2: Reflns within _diffrn_reflns_theta_max
         Count of symmetry unique reflns          745
         Completeness (_total/calc)             94.50%
          Alert C: < 95% complete

PLAT_302  Alert C Anion/Solvent Disorder .......................      28.00 Perc.

PLAT_601  Alert C Structure Contains Solvent Accessible VOIDS of      51.00 A   3

General Notes



FORMU_01  There is a discrepancy between the atom counts in the
          _chemical_formula_sum and _chemical_formula_moiety. This is
          usually due to the moiety formula being in the wrong format.
          Atom count from _chemical_formula_sum:   C4 H4 Ni1 O6.71
          Atom count from _chemical_formula_moiety:C4 H5.4 Ni1 O6.7

REFLT_03
         From the CIF: _diffrn_reflns_theta_max           26.50
         From the CIF: _reflns_number_total                704
         From the CIF: _diffrn_reflns_limit_ max hkl   20.   20.   16.
         From the CIF: _diffrn_reflns_limit_ min hkl   -8.  -16.  -14.
         TEST1: Expected hkl limits for theta max
         Calculated maximum hkl   20.   20.   20.
         Calculated minimum hkl  -20.  -20.  -20.
          ALERT: Expected hkl max differ from CIF values


 0 Alert Level A = Potentially serious problem

 0 Alert Level B = Potential problem

 3 Alert Level C = Please check

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Computing details

Data collection: IPDS Program Package (Stoe & Cie, 1998); cell refinement: IPDS Program Package; data reduction: IPDS Program Package; 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: CIFTAB in SHELXL97.

Poly[[diaqua(µ₄-squarato-O,O',O'',O''')nickel(II)] 0.71-hydrate]

Crystal data

[Ni(C4O4)(H2O)2]·0.71H2O	Mo Kα radiation, λ = 0.71073 Å
Mr = 218.12	Cell parameters from 8000 reflections
Cubic, Pn3n	θ = 2.5–26.5°
a = 16.1467 (8) Å	µ = 2.76 mm^−1
V = 4209.7 (4) Å^3	T = 293 K
Z = 24	Block, light green
F(000) = 2632	0.2 × 0.2 × 0.2 mm
Dx = 2.065 Mg m^−3

Data collection

Stoe IPDS diffractometer	508 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.026
Graphite monochromator	θmax = 26.5°, θmin = 1.8°
φ scans	h = −8→20
7475 measured reflections	k = −16→20
704 independent reflections	l = −14→16

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)] = 0.024	H-atom parameters constrained
wR(F^2) = 0.077	w = 1/[σ^2(Fo^2) + (0.0348P)^2 + 5.3938P] where P = (Fo^2 + 2Fc^2)/3
S = 1.07	(Δ/σ)max = 0.001
704 reflections	Δρmax = 0.48 e Å^−3
59 parameters	Δρmin = −0.46 e Å^−3
0 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: 0.00045 (9)

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.

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

	x	y	z	Uiso*/Ueq	Occ. (<1)
Ni	0.498248 (16)	0.498248 (16)	0.2500	0.0100 (2)
C1	0.30983 (15)	0.48345 (14)	0.22750 (14)	0.0148 (5)
O1	0.38197 (10)	0.48724 (11)	0.19876 (10)	0.0193 (4)
C2	0.50071 (15)	0.68953 (15)	0.22847 (15)	0.0173 (6)
O2	0.50353 (11)	0.61723 (10)	0.20048 (11)	0.0213 (5)
O3	0.46163 (10)	0.53619 (10)	0.36349 (10)	0.0182 (4)
H1	0.4158	0.5185	0.3765	0.027*
H2	0.4675	0.5845	0.3779	0.027*
O4	0.2500	0.6672 (15)	0.2500	0.132 (7)*	0.384 (19)
O5	0.2982 (15)	0.7047 (9)	0.2007 (15)	0.132 (7)*	0.258 (10)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ni	0.0103 (2)	0.0103 (2)	0.0095 (2)	−0.00010 (13)	−0.00017 (11)	0.00017 (11)
C1	0.0131 (12)	0.0197 (11)	0.0115 (12)	0.0011 (10)	−0.0005 (8)	−0.0008 (9)
O1	0.0096 (8)	0.0353 (10)	0.0130 (9)	0.0005 (7)	0.0003 (7)	0.0012 (7)
C2	0.0251 (13)	0.0135 (11)	0.0134 (13)	−0.0014 (10)	0.0010 (9)	0.0013 (8)
O2	0.0419 (12)	0.0097 (8)	0.0122 (9)	0.0006 (7)	0.0025 (7)	−0.0003 (7)
O3	0.0193 (9)	0.0183 (9)	0.0170 (8)	−0.0039 (7)	0.0070 (7)	−0.0048 (7)

Geometric parameters (Å, º)

Ni—O3^i	2.0206 (15)	C2—C2^v	1.466 (4)
Ni—O3	2.0206 (15)	O3—H1	0.8201
Ni—O1	2.0593 (16)	O3—H2	0.8200
Ni—O1^i	2.0593 (16)	O4—O5^ii	1.267 (19)
Ni—O2	2.0826 (17)	O4—O5^iii	1.267 (19)
Ni—O2^i	2.0826 (17)	O4—O5	1.267 (19)
C1—O1	1.255 (3)	O4—O5^vi	1.267 (19)
C1—C1^ii	1.460 (3)	O5—O5^vii	1.46 (3)
C1—C1^iii	1.460 (3)	O5—O5^ii	1.57 (3)
C2—O2	1.253 (3)	O5—O5^iii	1.57 (3)
C2—C2^iv	1.466 (4)
O3^i—Ni—O3	179.14 (10)	O2—C2—C2^iv	133.4 (2)
O3^i—Ni—O1	83.50 (6)	O2—C2—C2^v	136.6 (2)
O3—Ni—O1	97.11 (7)	C2^iv—C2—C2^v	89.986 (6)
O3^i—Ni—O1^i	97.11 (7)	C2—O2—Ni	136.03 (15)
O3—Ni—O1^i	83.50 (6)	Ni—O3—H1	113.0
O1—Ni—O1^i	90.23 (10)	Ni—O3—H2	120.9
O3^i—Ni—O2	84.80 (7)	H1—O3—H2	111.3
O3—Ni—O2	94.62 (7)	O5^ii—O4—O5^iii	123 (3)
O1—Ni—O2	87.86 (7)	O5^ii—O4—O5	76.8 (12)
O1^i—Ni—O2	177.14 (7)	O5^iii—O4—O5	76.8 (12)
O3^i—Ni—O2^i	94.62 (7)	O5^ii—O4—O5^vi	76.8 (12)
O3—Ni—O2^i	84.80 (7)	O5^iii—O4—O5^vi	76.8 (12)
O1—Ni—O2^i	177.14 (7)	O5—O4—O5^vi	123 (3)
O1^i—Ni—O2^i	87.86 (7)	O4—O5—O5^vii	118.5 (14)
O2—Ni—O2^i	94.12 (10)	O4—O5—O5^ii	51.6 (6)
O1—C1—C1^ii	133.8 (2)	O5^vii—O5—O5^ii	90.7 (14)
O1—C1—C1^iii	136.0 (2)	O4—O5—O5^iii	51.6 (6)
C1^ii—C1—C1^iii	90.000 (1)	O5^vii—O5—O5^iii	89.3 (15)
C1—O1—Ni	134.56 (15)	O5^ii—O5—O5^iii	90.000 (4)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H1···O1^iii	0.82	1.92	2.724 (2)	167
O3—H2···O2^v	0.82	1.93	2.730 (2)	164

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