Dipotassium nickel(II) bis­(di­hydrogendiphosphate) dihydrate, K₂Ni(H₂P₂O₇)₂·2H₂O

K₂Ni(H₂P₂O₇)₂·2H₂O is isostructural with its Zn analogue. Its structure is characterized by [Ni(H₂O)₂(H₂P₂O₇)₂]^2-coordin­ation units. These are linked by hydrogen bonds and K⁺ ions. Ni²⁺ is situated on an inversion centre and has an almost regular octahedral coordination.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](P-O) = 0.003 Å
• R factor = 0.044
• wR factor = 0.099
• Data-to-parameter ratio = 14.3

checkCIF/PLATON results

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Computing details

Data collection: SMART (Bruker, 1999); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ATOMS (Dowty, 1999); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997) and PLATOB (Spek, 1990).

Dipotasium nickel bis(dihydrogendiphosphate) dihydrate

Crystal data

K2Ni2(H2P2O7)2(H2O)2	Z = 1
Mr = 524.85	F(000) = 262
Triclinic, P1	Dx = 2.449 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 6.8554 (8) Å	Cell parameters from 1086 reflections
b = 7.3124 (9) Å	θ = 2.8–28.8°
c = 7.5610 (9) Å	µ = 2.48 mm^−1
α = 81.012 (2)°	T = 293 K
β = 72.301 (2)°	Needle, light-green
γ = 83.691 (2)°	0.28 × 0.06 × 0.05 mm
V = 355.87 (7) Å^3

Data collection

Bruker SMART APEX diffractometer	1757 independent reflections
Radiation source: fine-focus sealed tube	1290 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.046
Detector resolution: 8.33 pixels mm^-1	θmax = 28.3°, θmin = 2.8°
ω scans	h = −9→9
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	k = −9→9
Tmin = 0.692, Tmax = 0.883	l = −10→10
3793 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.044	Hydrogen site location: difference Fourier map
wR(F^2) = 0.099	H-atom parameters constrained
S = 0.96	w = 1/[σ^2(Fo^2) + (0.045P)^2] P = (Fo^2 + 2Fc^2)/3
1757 reflections	(Δ/σ)max < 0.001
123 parameters	Δρmax = 0.56 e Å^−3
4 restraints	Δρmin = −0.54 e Å^−3

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
K	0.89190 (16)	0.26756 (14)	0.70308 (14)	0.0343 (3)
Ni	0.5000	0.5000	0.5000	0.0171 (2)
P1	0.32676 (15)	0.27260 (14)	0.24671 (14)	0.0177 (2)
P2	0.75328 (15)	0.19077 (14)	0.24060 (14)	0.0172 (2)
O1	0.5669 (4)	0.2310 (4)	0.1500 (4)	0.0234 (6)
O2	0.2983 (4)	0.3920 (4)	0.3973 (4)	0.0207 (6)
O3	0.2424 (4)	0.3528 (4)	0.0886 (4)	0.0230 (6)
O4	0.2371 (5)	0.0813 (4)	0.3333 (4)	0.0256 (7)
H4	0.248 (7)	0.054 (7)	0.435 (5)	0.037 (15)*
O5	0.7435 (4)	0.3319 (4)	0.3681 (4)	0.0229 (6)
O6	0.9340 (4)	0.2145 (4)	0.0597 (4)	0.0239 (6)
H6	1.021 (6)	0.270 (7)	0.068 (8)	0.048 (17)*
O7	0.7472 (4)	−0.0067 (4)	0.3329 (4)	0.0263 (7)
O1W	0.5489 (5)	0.7052 (4)	0.2727 (4)	0.0237 (7)
H1W	0.608 (7)	0.674 (7)	0.174 (5)	0.036 (15)*
H2W	0.596 (7)	0.792 (5)	0.286 (7)	0.036 (15)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
K	0.0414 (6)	0.0312 (6)	0.0335 (6)	0.0084 (4)	−0.0185 (5)	−0.0060 (5)
Ni	0.0183 (4)	0.0166 (4)	0.0171 (4)	−0.0004 (3)	−0.0059 (3)	−0.0035 (3)
P1	0.0170 (5)	0.0194 (5)	0.0183 (5)	−0.0010 (4)	−0.0073 (4)	−0.0034 (4)
P2	0.0169 (5)	0.0186 (5)	0.0161 (5)	0.0000 (4)	−0.0050 (4)	−0.0031 (4)
O1	0.0181 (14)	0.0336 (17)	0.0210 (15)	0.0028 (12)	−0.0087 (12)	−0.0080 (13)
O2	0.0172 (14)	0.0226 (15)	0.0224 (15)	−0.0014 (11)	−0.0047 (11)	−0.0052 (12)
O3	0.0242 (15)	0.0270 (16)	0.0191 (14)	−0.0052 (12)	−0.0092 (12)	0.0017 (12)
O4	0.0355 (18)	0.0192 (15)	0.0243 (17)	−0.0070 (13)	−0.0119 (14)	0.0007 (13)
O5	0.0210 (15)	0.0277 (16)	0.0227 (15)	0.0038 (12)	−0.0083 (12)	−0.0115 (13)
O6	0.0214 (15)	0.0313 (17)	0.0189 (15)	−0.0062 (13)	−0.0030 (13)	−0.0056 (13)
O7	0.0359 (17)	0.0202 (15)	0.0238 (15)	−0.0073 (13)	−0.0118 (13)	0.0040 (12)
O1W	0.0312 (17)	0.0197 (16)	0.0184 (16)	−0.0038 (13)	−0.0036 (13)	−0.0032 (13)

Geometric parameters (Å, º)

K—O6^i	2.761 (3)	P1—O1	1.602 (3)
K—O2^ii	2.788 (3)	P2—O7	1.501 (3)
K—O4^iii	2.869 (3)	P2—O5	1.502 (3)
K—O7^iv	2.924 (3)	P2—O6	1.542 (3)
K—O1W^ii	2.958 (3)	P2—O1	1.604 (3)
K—O5	2.960 (3)	O2—K^ii	2.788 (3)
K—O2^v	3.149 (3)	O2—K^vi	3.149 (3)
K—O3^ii	3.311 (3)	O3—K^ii	3.311 (3)
Ni—O5^ii	2.052 (3)	O4—K^iii	2.869 (3)
Ni—O5	2.052 (3)	O4—H4	0.79 (3)
Ni—O2^ii	2.055 (3)	O6—K^vii	2.761 (3)
Ni—O2	2.055 (3)	O6—H6	0.78 (3)
Ni—O1W	2.067 (3)	O7—K^iv	2.924 (3)
Ni—O1W^ii	2.067 (3)	O1W—K^ii	2.958 (3)
P1—O2	1.495 (3)	O1W—H1W	0.79 (3)
P1—O3	1.495 (3)	O1W—H2W	0.77 (3)
P1—O4	1.556 (3)
O6^i—K—O2^ii	115.34 (9)	O2^ii—Ni—O1W^ii	88.63 (12)
O6^i—K—O4^iii	103.55 (9)	O2—Ni—O1W^ii	91.37 (12)
O2^ii—K—O4^iii	123.02 (9)	O1W—Ni—O1W^ii	180.0
O6^i—K—O7^iv	77.33 (9)	O2—P1—O3	116.38 (16)
O2^ii—K—O7^iv	151.46 (9)	O2—P1—O4	110.01 (17)
O4^iii—K—O7^iv	74.07 (8)	O3—P1—O4	109.28 (16)
O6^i—K—O1W^ii	109.37 (9)	O2—P1—O1	109.40 (15)
O2^ii—K—O1W^ii	60.07 (8)	O3—P1—O1	104.78 (15)
O4^iii—K—O1W^ii	68.84 (9)	O4—P1—O1	106.44 (16)
O7^iv—K—O1W^ii	142.86 (9)	O7—P2—O5	114.66 (17)
O6^i—K—O5	166.61 (9)	O7—P2—O6	111.44 (17)
O2^ii—K—O5	58.82 (8)	O5—P2—O6	112.52 (17)
O4^iii—K—O5	73.65 (9)	O7—P2—O1	107.50 (16)
O7^iv—K—O5	113.64 (8)	O5—P2—O1	110.49 (15)
O1W^ii—K—O5	57.29 (8)	O6—P2—O1	98.98 (16)
O6^i—K—O2^v	112.09 (8)	P1—O1—P2	130.13 (18)
O2^ii—K—O2^v	88.13 (8)	P1—O2—Ni	133.08 (16)
O4^iii—K—O2^v	114.51 (8)	P1—O2—K^ii	108.45 (14)
O7^iv—K—O2^v	63.35 (8)	Ni—O2—K^ii	95.80 (10)
O1W^ii—K—O2^v	135.72 (8)	P1—O2—K^vi	104.60 (13)
O5—K—O2^v	80.54 (7)	Ni—O2—K^vi	114.33 (10)
O6^i—K—O3^ii	67.56 (8)	K^ii—O2—K^vi	91.87 (8)
O2^ii—K—O3^ii	48.31 (7)	P1—O3—K^ii	86.80 (12)
O4^iii—K—O3^ii	145.29 (9)	P1—O4—K^iii	151.30 (17)
O7^iv—K—O3^ii	131.24 (8)	P1—O4—H4	110 (4)
O1W^ii—K—O3^ii	82.30 (8)	K^iii—O4—H4	97 (4)
O5—K—O3^ii	107.00 (7)	P2—O5—Ni	129.99 (16)
O2^v—K—O3^ii	99.50 (7)	P2—O5—K	125.63 (14)
O5^ii—Ni—O5	180.0	Ni—O5—K	90.85 (9)
O5^ii—Ni—O2^ii	93.03 (10)	P2—O6—K^vii	124.22 (16)
O5—Ni—O2^ii	86.97 (10)	P2—O6—H6	114 (4)
O5^ii—Ni—O2	86.97 (10)	K^vii—O6—H6	113 (4)
O5—Ni—O2	93.03 (10)	P2—O7—K^iv	124.07 (15)
O2^ii—Ni—O2	180.00 (13)	Ni—O1W—K^ii	90.63 (11)
O5^ii—Ni—O1W	87.06 (12)	Ni—O1W—H1W	117 (4)
O5—Ni—O1W	92.94 (12)	K^ii—O1W—H1W	106 (4)
O2^ii—Ni—O1W	91.37 (12)	Ni—O1W—H2W	114 (4)
O2—Ni—O1W	88.63 (12)	K^ii—O1W—H2W	118 (4)
O5^ii—Ni—O1W^ii	92.94 (12)	H1W—O1W—H2W	109 (5)
O5—Ni—O1W^ii	87.06 (12)
O2—P1—O1—P2	38.3 (3)	O7—P2—O5—K	28.4 (2)
O3—P1—O1—P2	163.7 (2)	O6—P2—O5—K	−100.3 (2)
O4—P1—O1—P2	−80.6 (3)	O1—P2—O5—K	150.10 (15)
O7—P2—O1—P1	77.6 (3)	O2^ii—Ni—O5—P2	−178.2 (2)
O5—P2—O1—P1	−48.2 (3)	O2—Ni—O5—P2	1.8 (2)
O6—P2—O1—P1	−166.4 (2)	O1W—Ni—O5—P2	−87.0 (2)
O3—P1—O2—Ni	−120.1 (2)	O1W^ii—Ni—O5—P2	93.0 (2)
O4—P1—O2—Ni	114.9 (2)	O2^ii—Ni—O5—K	41.13 (9)
O1—P1—O2—Ni	−1.7 (3)	O2—Ni—O5—K	−138.87 (9)
O3—P1—O2—K^ii	−2.90 (19)	O1W—Ni—O5—K	132.36 (10)
O4—P1—O2—K^ii	−127.86 (15)	O1W^ii—Ni—O5—K	−47.64 (10)
O1—P1—O2—K^ii	115.55 (14)	O6^i—K—O5—P2	−110.2 (4)
O3—P1—O2—K^vi	94.13 (16)	O2^ii—K—O5—P2	−177.7 (2)
O4—P1—O2—K^vi	−30.83 (17)	O4^iii—K—O5—P2	−30.47 (17)
O1—P1—O2—K^vi	−147.42 (13)	O7^iv—K—O5—P2	33.4 (2)
O5^ii—Ni—O2—P1	166.6 (2)	O1W^ii—K—O5—P2	−105.5 (2)
O5—Ni—O2—P1	−13.4 (2)	O2^v—K—O5—P2	88.69 (18)
O1W—Ni—O2—P1	79.5 (2)	O3^ii—K—O5—P2	−174.19 (16)
O1W^ii—Ni—O2—P1	−100.5 (2)	O6^i—K—O5—Ni	33.0 (4)
O5^ii—Ni—O2—K^ii	44.59 (10)	O2^ii—K—O5—Ni	−34.48 (8)
O5—Ni—O2—K^ii	−135.41 (10)	O4^iii—K—O5—Ni	112.80 (11)
O1W—Ni—O2—K^ii	−42.54 (11)	O7^iv—K—O5—Ni	176.66 (9)
O1W^ii—Ni—O2—K^ii	137.46 (11)	O1W^ii—K—O5—Ni	37.80 (9)
O5^ii—Ni—O2—K^vi	−50.10 (12)	O2^v—K—O5—Ni	−128.05 (10)
O5—Ni—O2—K^vi	129.90 (12)	O3^ii—K—O5—Ni	−30.92 (11)
O1W—Ni—O2—K^vi	−137.23 (12)	O7—P2—O6—K^vii	106.57 (19)
O1W^ii—Ni—O2—K^vi	42.77 (12)	O5—P2—O6—K^vii	−123.03 (18)
O2—P1—O3—K^ii	2.32 (16)	O1—P2—O6—K^vii	−6.3 (2)
O4—P1—O3—K^ii	127.65 (14)	O5—P2—O7—K^iv	−101.83 (18)
O1—P1—O3—K^ii	−118.63 (12)	O6—P2—O7—K^iv	27.5 (2)
O2—P1—O4—K^iii	167.8 (3)	O1—P2—O7—K^iv	134.90 (16)
O3—P1—O4—K^iii	38.9 (4)	O5^ii—Ni—O1W—K^ii	−47.69 (9)
O1—P1—O4—K^iii	−73.8 (4)	O5—Ni—O1W—K^ii	132.31 (9)
O7—P2—O5—Ni	−100.2 (2)	O2^ii—Ni—O1W—K^ii	−140.66 (9)
O6—P2—O5—Ni	131.0 (2)	O2—Ni—O1W—K^ii	39.34 (9)
O1—P2—O5—Ni	21.4 (3)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O4—H4···O7^iii	0.79 (3)	1.74 (3)	2.530 (4)	175 (5)
O6—H6···O3^v	0.78 (3)	1.75 (3)	2.522 (4)	169 (6)
O1W—H1W···O3^viii	0.79 (3)	1.97 (3)	2.746 (4)	169 (5)
O1W—H2W···O7^ix	0.77 (3)	2.02 (3)	2.793 (4)	172 (5)

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