Dipotassium hexa­aqua­nickel(II) bis­[hexa­fluoridozirconate(IV)]

Oudahmane, A.; Mnaouer, N.; El-Ghozzi, M.; Avignant, D.

doi:10.1107/S160053681005350X

inorganic compounds

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Volume 67| Part 1| January 2011| Pages i6-i7

https://doi.org/10.1107/S160053681005350X

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Dipotassium hexaaquanickel(II) bis[hexafluoridozirconate(IV)]

Abdelghani Oudahmane,^a Noura Mnaouer,^a Malika El-Ghozzi ^a and Daniel Avignant ^a ^*

^aUniversité Blaise Pascal, Laboratoire des Matériaux Inorganiques, UMR CNRS 6002, 24 Avenue des Landais, 63177 Aubière, France
^*Correspondence e-mail: daniel.avignant@univ-bpclermont.fr

(Received 13 December 2010; accepted 20 December 2010; online 24 December 2010)

Single crystals of the title compound, K₂[Ni(H₂O)₆][ZrF₆]₂, were grown by slow evaporation of a 40% aqueous HF solution in which a stoichiometric mixture of NiCl₂·6H₂O, ZrF₄ and KCl was dissolved. The monoclinic structure is isotypic with its K₂Cu, K₂Zn, Cs₂Zn and Cs₂Cu analogues. The structure is built up from isolated, slightly elongated octahedral [Ni(H₂O)₆]²⁺ complex cations (symmetry $[\overline{1}]$ ) and dimeric [Zr₂F₁₂]⁴⁻ complex anions (symmetry $[\overline{1}]$ ) that are also isolated from each other. The [Zr₂F₁₂]⁴⁻ anion results from the association of two distorted pentagonal–bipyramidal [ZrF₇] coordination polyhedra by sharing an equatorial edge passing through an inversion center of the unit cell. Both isolated [Ni(H₂O)₆]²⁺ and [Zr₂F₁₂]⁴⁻ complex ions are situated in planes parallel to (010). They are connected by the eight-coordinated K⁺ ions into a three-dimensional structure. An intricate O—H⋯F hydrogen-bonding network consolidates the structure.

Related literature

For isotypic structures, see: Fischer & Weiss (1973 ); Bukvetskii et al. (1993 ); Hitchman et al. (2002 ). For a review on the stereochemistry of zirconium and hafnium fluorido complexes, see: Davidovich (1998 ). For background to distortion indices, see: Momma & Izumi (2008 ).

Experimental

Crystal data

K₂[Ni(H₂O)₆][ZrF₆]₂
M_r = 655.45
Monoclinic, P 2₁ /n
a = 6.6090 (1) Å
b = 10.0398 (1) Å
c = 11.7843 (1) Å
β = 95.897 (1)°
V = 777.79 (2) Å³
Z = 2
Mo Kα radiation
μ = 3.20 mm⁻¹
T = 296 K
0.28 × 0.14 × 0.09 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2008 ) T_min = 0.613, T_max = 0.748
17267 measured reflections
4436 independent reflections
3858 reflections with I > 2σ(I)
R_int = 0.028

Refinement

R[F² > 2σ(F²)] = 0.023
wR(F²) = 0.052
S = 1.06
4436 reflections
131 parameters
All H-atom parameters refined
Δρ_max = 0.63 e Å⁻³
Δρ_min = −0.57 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H11⋯F1ⁱ	0.79 (3)	2.94 (2)	3.3300 (14)	112.8 (19)
O1—H11⋯F2ⁱⁱ	0.79 (3)	1.92 (3)	2.6877 (14)	164 (2)
O1—H12⋯F4ⁱⁱⁱ	0.82 (3)	1.82 (3)	2.6375 (13)	177 (2)
O1—H12⋯F5^iv	0.82 (3)	2.61 (2)	3.0526 (13)	116 (2)
O2—H21⋯F1ⁱ	0.78 (2)	2.59 (2)	3.0048 (13)	115 (2)
O2—H21⋯F2ⁱⁱ	0.78 (2)	1.95 (2)	2.7227 (13)	167 (2)
O2—H22⋯F4^v	0.82 (2)	1.92 (2)	2.7362 (13)	173 (2)
O2—H22⋯F6^vi	0.82 (2)	2.76 (2)	3.1924 (14)	114.9 (17)
O3—H31⋯F1^vii	0.80 (3)	2.86 (3)	3.2552 (16)	113.3 (19)
O3—H31⋯F5^viii	0.80 (3)	1.92 (3)	2.7019 (14)	168 (2)
O3—H32⋯F3^iv	0.80 (3)	3.00 (2)	3.4527 (16)	119 (2)
O3—H32⋯F6^ix	0.80 (3)	1.97 (3)	2.7427 (15)	163 (2)
Symmetry codes: (i) $[-x+{\script{1\over 2}}, y-{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (ii) $[x+{\script{1\over 2}}, -y+{\script{1\over 2}}, z-{\script{1\over 2}}]$ ; (iii) -x, -y+1, -z; (iv) -x, -y, -z; (v) -x-1, -y+1, -z; (vi) -x-1, -y, -z; (vii) $[x-{\script{1\over 2}}, -y-{\script{1\over 2}}, z-{\script{1\over 2}}]$ ; (viii) $[x+{\script{1\over 2}}, -y-{\script{1\over 2}}, z-{\script{1\over 2}}]$ ; (ix) -x-1, -y-1, -z.

Table 2
Comparison of the geometrical characteristics of the coordination polyhedra in isotypic M^I₂[M^II(H₂O)₆][ZrF₆]₂ structures determined from single-crystal data (Å, °, Å³)

	K₂[Ni(H₂O)₆][ZrF₆]₂^a	K₂[Cu(H₂O)₆][ZrF₆]₂^b	K₂[Zn(H₂O)₆][ZrF₆]₂^c	Cs₂[Zn(H₂O)₆][ZrF₆]₂^d
Space group	P2₁/n	P2₁/c	P2₁/c	P2₁/n
a	6.6090 (1)	6.631 (6)	6.631 (1)	6.970 (1)
b	10.0398 (1)	9.981 (10)	10.071 (1)	10.515 (2)
c	11.7843 (1)	12.921 (12)	12.952 (1)	11.803 (2)
β	95.897 (1)	114.20 (15)	114.96 (2)	93.56 (3)
V	777.786 (16)	780.01 (1)	784.16 (2)	863.4 (3)
	Ni—O1 = 2.0548 (10) (2×)	Cu—O1 = 1.966 (4) (2×)	Zn—O1 = 2.0856 (2) (2×)	Zn—O3 = 2.096 (6) (2×)
Distances M^II—O	Ni—O3 = 2.0570 (11) (2×)	Cu—O2 = 2.025 (6) (2×)	Zn—O2 = 2.0940 (1) (2×)	Zn—O1 = 2.099 (5) (2×)
	Ni—O2 = 2.0781 (9) (2×)	Cu—O3 = 2.327 (5) (2×)	Zn—O3 = 2.1185 (2) (2×)	Zn—O2 = 2.105 (5) (2×)
Average M^II—O bond length	2.063	2.106	2.099	2.100
Polyhedral volume	11.684	12.335	12.318	12.341
Distortion index (bond length)	0.00483	0.06089	0.00607	0.00156
Quadratic elongation	1.0013	1.0124	1.0011	1.0006
	Zr—F6 = 1.9718 (9)	Zr—F3 = 1.968 (5)	Zr—F3 = 1.9727 (3)	Zr—F3 = 1.962 (5)
	Zr—F5 = 2.0006 (8)	Zr—F1 = 2.004 (5)	Zr—F1 = 2.0018 (3)	Zr—F6 = 1.977 (5)
	Zr—F3 = 2.0293 (9)	Zr—F5 = 2.029 (4)	Zr—F5 = 2.0277 (3)	Zr—F5 = 2.037 (5)
Distances Zr—F (Å)	Zr—F2 = 2.0554 (8)	Zr—F6 = 2.059 (4)	Zr—F6 = 2.0570 (3)	Zr—F4 = 2.067 (4)
	Zr—F1 = 2.0708 (8)	Zr—F2 = 2.063 (4)	Zr—F2 = 2.0668 (4)	Zr—F2 = 2.069 (4)
	Zr—F4 = 2.1468 (9)	Zr—F4 = 2.156 (5)	Zr—F4 = 2.1501 (4)	Zr—F1 = 2.156 (4)
	Zr—F4 = 2.1614 (8)	Zr—F4 = 2.160 (4)	Zr—F4 = 2.1628 (4)	Zr—F1 = 2.180 (4)
Average Zr—F bond length	2.062	2.063	2.063	2.064
Polyhedral volume	13.669	13.674	13.675	13.692
Distortion index (bond length)	0.02662	0.02650	0.02654	0.02985
	K—F5 = 2.6496 (10)	K—F1 = 2.668 (5)	K—F1 = 2.6506 (3)	Cs—F6 = 2.911 (5)
	K—F3 = 2.7366 (9)	K—F6 = 2.750 (6)	K—F2 = 2.7395 (4)	Cs—F4 = 3.046 (4)
	K—F6 = 2.7603 (11)	K—F3 = 2.756 (5)	K—F5 = 2.7633 (2)	Cs—F2 = 3.057 (4)
Distances K—F/O	K—F2 = 2.7658 (9)	K—F5 = 2.767 (5)	K—F6 = 2.7739 (2)	Cs—F3 = 3.065 (5)
	K—F1 = 2.7895 (9)	K—F2 = 2.799 (5)	K—F3 = 2.8094 (2)	Cs—F3 = 3.102 (5)
	K—O2 = 2.8927 (10)	K—O3 = 2.942 (5)	K—O1 = 2.8968 (3)	Cs—O2 = 3.218 (5)
	K—O1 = 3.1012 (10)	K—O1 = 2.980 (5)	K—O2 = 3.0873 (5)	Cs—O1 = 3.236 (5)
	K—F6 = 3.1684 (12)	K—F3 = 3.1307 (7)	K—F3 = 3.1707 (7)	Cs—F5 = 3.228 (6)
Average M^I—F/O bond length	2.858	2.849	2.861	3.118
Polyhedral volume	38.458	38.158	38.569	48.130
Distortion index (bond length)	0.05146	0.04429	0.04984	0.02627
Notes: (a) this work; (b) Fischer & Weiss (1973); (c) Bukvetskii et al. (1993); (d) Hitchman et al. (2002).

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 1999 ) and ORTEP-3 for Windows (Farrugia, 1997 ); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Supporting information

Crystal structure: contains datablocks I, global. DOI: https://doi.org/10.1107/S160053681005350X/wm2439sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S160053681005350X/wm2439Isup2.hkl

checkCIF report

Comment top

The existence of the title compound K₂[Ni(H₂O)₆][ZrF₆]₂ as member of the large family of zirconium fluorido complexes with general formula M^I₂[M^II(H₂O)₆][ZrF₆]₂ where M^I = K, Rb, Cs or NH₄ and M^II = Co, Ni, Cu or Zn, has already been mentioned by Davidovich (1998). The monoclinic structure of the title compound is isotypic with those of K₂[Cu(H₂O)₆][ZrF₆]₂ (Fischer & Weiss, 1973), K₂[Zn(H₂O)₆][ZrF₆]₂ (Bukvetskii et al., 1993) and Cs₂[Zn(H₂O)₆][ZrF₆]₂ (Hitchman et al., 2002). In the title structure the Ni²⁺ cation (site symmetry 1) is coordinated by six water molecules with two Ni—O distances slightly longer (2.0781 (9) Å) than the four others (2x 2.0548 (10) Å and 2x 2.0570 (11) Å). The Zr⁴⁺ cation is 7-coordinated by the fluoride ions but rather than being isolated anions, the fluoridozirconate(IV) ions form centrosymmetric [Zr₂F₁₂]^4- dimers. Thus the structure is built up from isolated and slightly elongated octahedral [Ni(H₂O)₆]²⁺ complex cations and dimeric [Zr₂F₁₂]^4- complex anions, also isolated from each other. The [ZrF₇] coordination polyhedron is a distorted pentagonal bipyramid (symmetry 1) and the centrosymmetric [Zr₂F₁₂]^4- complex anion results from the association of two pentagonal bipyramids by sharing an equatorial edge F1—F1 passing through an inversion center of the unit cell corresponding to either the 2 b or 2 c Wyckoff positions. Both isolated [Ni(H₂O)₆]²⁺ and [Zr₂F₁₂]^4- complex ions lying in planes parallel to (010) are connected by the 8-coordinated K⁺ ions (Fig. 1) and an intricate O—H···F hydrogen bonds network (Fig. 2 and Table 1) to form the three-dimensional structure.

A careful examination of the geometry of the [Zr₂F₁₂]^4- complex anion in isotypic structures, refined from single-crystal data, shows this anion being quasi unvarying for all the members (Table 2). The distortion index (bond length) (Momma & Izumi, 2008) is the same for all the K compounds (0.0265) and is only very slightly higher (0.02985) for the Cs analogue. It is also worth noting that the higher the index of distortion of the [M^II(H₂O)₆] cationic polyhedron, the lower the index of distortion of the counter cation K⁺ (0.04429). This observation is obvious because water molecules are only shared between K⁺ and M²⁺ ions.

Related literature top

For isotypic structures, see: Fischer & Weiss (1973); Bukvetskii et al. (1993); Hitchman et al. (2002). For a review on the stereochemistry of zirconium and hafnium fluorido complexes, see: Davidovich (1998). For background to distortion indices, see: Momma & Izumi (2008).

Experimental top

Single crystals of the title compound were obtained by reacting a mixture of NiCl₂.6H₂O, ZrF₄ and KCl in the molar ratio 1:2:2 with a 40% aqueous HF boiling solution in a platinum crucible. Then the solution was poured out into a PTFE beaker and slowly evaporated to dryness using a sand bath. Green single-crystals of the title compound were extracted from the dry residue.

Structure description top

For isotypic structures, see: Fischer & Weiss (1973); Bukvetskii et al. (1993); Hitchman et al. (2002). For a review on the stereochemistry of zirconium and hafnium fluorido complexes, see: Davidovich (1998). For background to distortion indices, see: Momma & Izumi (2008).

Computing details top

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 1999) and ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

Fig. 1. View of the polyhedral linkage inK₂[Ni(H₂O)₆][ZrF₆]₂. Displacement ellipsoids are drawn at the 50% probability level. Symmetry codes: (i) x, y + 1, z; (ii) x - 1, y + 1, z; (iii) -x, -y + 1, -z + 1; (iv) -x, -y, -z; (v) -x, -y - 1, -z; (vi) -x - 1/2, y + 1/2, -z + 1/2; (vii) -x + 1/2, y + 1/2, -z + 1/2; (viii) x + 1/2, -y + 3/2, z - 1/2; (x) x + 1, y + 1, z; (xi) -x + 1/2, y - 1/2, -z + 1/2; (xii) x, y - 1, z; (xiii) x - 1, y - 1, z; (xiv) x + 1, y - 1, z; (xv) x - 1, y, z; (xvi) x - 1/2, -y + 3/2, z + 1/2; (xvii) -x - 1/2, y - 1/2, -z + 1/2.

Fig. 2. Projection of the crystal structure of K₂[Ni(H₂O)₆][ZrF₆]₂ along [100] showing the hydrogen-bonding interactions.

Dipotassium hexaaquanickel bis[hexafluoridozirconate(IV)] top

Crystal data top

K₂[Ni(H₂O)₆][ZrF₆]₂	F(000) = 628
M_r = 655.45	D_x = 2.799 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 7940 reflections
a = 6.6090 (1) Å	θ = 3.7–38.7°
b = 10.0398 (1) Å	µ = 3.20 mm⁻¹
c = 11.7843 (1) Å	T = 296 K
β = 95.897 (1)°	Block, green
V = 777.79 (2) Å³	0.28 × 0.14 × 0.09 mm
Z = 2

Data collection top

Bruker APEXII CCD diffractometer	4436 independent reflections
Radiation source: fine-focus sealed tube	3858 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.028
Detector resolution: 8.3333 pixels mm^-1	θ_max = 38.8°, θ_min = 4.2°
ω and φ scans	h = −11→11
Absorption correction: multi-scan (SADABS; Bruker, 2008)	k = −17→12
T_min = 0.613, T_max = 0.748	l = −18→20
17267 measured reflections

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F² > 2σ(F²)] = 0.023	All H-atom parameters refined
wR(F²) = 0.052	w = 1/[σ²(F_o²) + (0.0182P)² + 0.3179P] where P = (F_o² + 2F_c²)/3
S = 1.06	(Δ/σ)_max = 0.032
4436 reflections	Δρ_max = 0.63 e Å⁻³
131 parameters	Δρ_min = −0.57 e Å⁻³
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
0 constraints	Extinction coefficient: 0.0068 (4)
Primary atom site location: structure-invariant direct methods

Crystal data top

K₂[Ni(H₂O)₆][ZrF₆]₂	V = 777.79 (2) Å³
M_r = 655.45	Z = 2
Monoclinic, P2₁/n	Mo Kα radiation
a = 6.6090 (1) Å	µ = 3.20 mm⁻¹
b = 10.0398 (1) Å	T = 296 K
c = 11.7843 (1) Å	0.28 × 0.14 × 0.09 mm
β = 95.897 (1)°

Data collection top

Bruker APEXII CCD diffractometer	4436 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2008)	3858 reflections with I > 2σ(I)
T_min = 0.613, T_max = 0.748	R_int = 0.028
17267 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.023	0 restraints
wR(F²) = 0.052	All H-atom parameters refined
S = 1.06	Δρ_max = 0.63 e Å⁻³
4436 reflections	Δρ_min = −0.57 e Å⁻³
131 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.

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 (Å²) top

	x	y	z	U_iso*/U_eq
Zr	−0.462200 (17)	0.984514 (11)	0.350424 (9)	0.01376 (3)
Ni	0.0000	0.0000	0.0000	0.01508 (4)
K	0.47534 (5)	0.71630 (3)	0.08423 (3)	0.02839 (7)
O1	0.21314 (15)	−0.11683 (10)	−0.06747 (9)	0.02154 (17)
O2	−0.23852 (15)	−0.12500 (10)	−0.05901 (9)	0.02039 (17)
O3	−0.04437 (19)	−0.88871 (12)	−0.14701 (9)	0.0293 (2)
F1	0.53736 (16)	0.11314 (9)	0.49592 (7)	0.0300 (2)
F2	−0.53154 (14)	0.78950 (8)	0.31006 (7)	0.02440 (16)
F3	−0.17901 (13)	0.93040 (11)	0.39692 (9)	0.0346 (2)
F4	−0.46635 (13)	0.97177 (8)	0.17481 (7)	0.02228 (15)
F5	−0.35001 (14)	0.16232 (8)	0.30407 (8)	0.02609 (17)
F6	−0.75507 (12)	0.03609 (11)	0.31945 (8)	0.02759 (18)
H11	0.159 (4)	−0.169 (3)	−0.111 (2)	0.044 (6)*
H12	0.289 (4)	−0.072 (3)	−0.103 (2)	0.044 (6)*
H21	−0.196 (3)	−0.178 (2)	−0.099 (2)	0.041 (6)*
H22	−0.327 (3)	−0.084 (2)	−0.0981 (19)	0.038 (6)*
H31	0.028 (4)	−0.829 (3)	−0.163 (2)	0.046 (7)*
H32	−0.086 (4)	−0.925 (3)	−0.205 (2)	0.048 (7)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Zr	0.01662 (5)	0.01302 (5)	0.01144 (5)	−0.00068 (3)	0.00044 (3)	0.00045 (3)
Ni	0.01666 (9)	0.01442 (9)	0.01395 (9)	−0.00119 (6)	0.00064 (7)	−0.00028 (6)
K	0.03371 (15)	0.02741 (14)	0.02299 (14)	−0.00580 (11)	−0.00224 (11)	0.00113 (10)
O1	0.0229 (4)	0.0194 (4)	0.0230 (5)	−0.0021 (3)	0.0058 (4)	−0.0031 (3)
O2	0.0207 (4)	0.0186 (4)	0.0213 (4)	−0.0003 (3)	−0.0007 (3)	−0.0024 (3)
O3	0.0407 (6)	0.0279 (5)	0.0175 (5)	−0.0127 (4)	−0.0053 (4)	0.0056 (4)
F1	0.0579 (6)	0.0175 (4)	0.0158 (4)	−0.0105 (4)	0.0091 (4)	−0.0021 (3)
F2	0.0394 (5)	0.0162 (3)	0.0173 (4)	−0.0029 (3)	0.0014 (3)	−0.0013 (3)
F3	0.0216 (4)	0.0442 (6)	0.0365 (5)	0.0060 (4)	−0.0048 (3)	0.0052 (4)
F4	0.0280 (4)	0.0239 (4)	0.0152 (3)	−0.0041 (3)	0.0037 (3)	−0.0007 (3)
F5	0.0367 (4)	0.0181 (4)	0.0247 (4)	−0.0067 (3)	0.0091 (3)	0.0002 (3)
F6	0.0193 (4)	0.0350 (5)	0.0280 (5)	0.0055 (3)	0.0004 (3)	−0.0062 (3)

Geometric parameters (Å, º) top

Zr—F3	1.9717 (9)	K—F3^xi	3.1685 (12)
Zr—F6ⁱ	2.0006 (8)	O1—K^xii	2.8929 (11)
Zr—F5ⁱ	2.0293 (8)	O1—H11	0.79 (3)
Zr—F2	2.0554 (8)	O1—H12	0.82 (3)
Zr—F4	2.0708 (8)	O2—K^xiii	3.1015 (11)
Zr—F1ⁱⁱ	2.1467 (8)	O2—H21	0.78 (2)
Zr—F1ⁱⁱⁱ	2.1614 (8)	O2—H22	0.82 (2)
Ni—O1^iv	2.0548 (10)	O3—Ni^xii	2.0570 (11)
Ni—O1	2.0548 (10)	O3—H31	0.80 (3)
Ni—O3^v	2.0570 (11)	O3—H32	0.80 (3)
Ni—O3ⁱ	2.0570 (11)	F1—Zr^xiv	2.1467 (8)
Ni—O2^iv	2.0781 (9)	F1—Zrⁱⁱⁱ	2.1614 (8)
Ni—O2	2.0781 (9)	F2—K^xv	2.7658 (9)
K—F6^vi	2.6497 (9)	F3—K^xvi	2.7603 (10)
K—F5^vii	2.7365 (10)	F3—K^vii	3.1685 (12)
K—F3^viii	2.7603 (10)	F4—K^xv	2.7896 (9)
K—F2^ix	2.7658 (9)	F5—Zr^xii	2.0293 (8)
K—F4^ix	2.7896 (9)	F5—K^xi	2.7365 (10)
K—O1ⁱ	2.8929 (11)	F6—Zr^xii	2.0006 (8)
K—O2^x	3.1015 (11)	F6—K^xvii	2.6497 (9)

F3—Zr—F6ⁱ	174.24 (4)	F5^vii—K—F2^ix	72.14 (3)
F3—Zr—F5ⁱ	87.40 (4)	F3^viii—K—F2^ix	150.45 (3)
F6ⁱ—Zr—F5ⁱ	95.54 (4)	F6^vi—K—F4^ix	121.62 (3)
F3—Zr—F2	89.11 (4)	F5^vii—K—F4^ix	85.15 (3)
F6ⁱ—Zr—F2	90.90 (4)	F3^viii—K—F4^ix	145.26 (3)
F5ⁱ—Zr—F2	148.71 (3)	F2^ix—K—F4^ix	53.33 (2)
F3—Zr—F4	100.10 (4)	F6^vi—K—O1ⁱ	109.85 (3)
F6ⁱ—Zr—F4	85.44 (4)	F5^vii—K—O1ⁱ	150.10 (3)
F5ⁱ—Zr—F4	75.70 (3)	F3^viii—K—O1ⁱ	70.50 (3)
F2—Zr—F4	74.34 (3)	F2^ix—K—O1ⁱ	111.88 (3)
F3—Zr—F1ⁱⁱ	91.31 (4)	F4^ix—K—O1ⁱ	75.79 (3)
F6ⁱ—Zr—F1ⁱⁱ	84.80 (4)	F6^vi—K—O2^x	167.54 (3)
F5ⁱ—Zr—F1ⁱⁱ	73.52 (3)	F5^vii—K—O2^x	77.96 (3)
F2—Zr—F1ⁱⁱ	137.67 (3)	F3^viii—K—O2^x	92.00 (3)
F4—Zr—F1ⁱⁱ	146.55 (3)	F2^ix—K—O2^x	117.28 (3)
F3—Zr—F1ⁱⁱⁱ	86.30 (4)	F4^ix—K—O2^x	70.61 (3)
F6ⁱ—Zr—F1ⁱⁱⁱ	88.22 (4)	O1ⁱ—K—O2^x	74.11 (3)
F5ⁱ—Zr—F1ⁱⁱⁱ	138.27 (3)	F6^vi—K—F3^xi	66.39 (3)
F2—Zr—F1ⁱⁱⁱ	72.35 (3)	F5^vii—K—F3^xi	55.25 (2)
F4—Zr—F1ⁱⁱⁱ	145.96 (3)	F3^viii—K—F3^xi	72.07 (3)
F1ⁱⁱ—Zr—F1ⁱⁱⁱ	65.45 (4)	F2^ix—K—F3^xi	102.83 (3)
F3—Zr—Zr^xviii	88.57 (3)	F4^ix—K—F3^xi	139.92 (3)
F6ⁱ—Zr—Zr^xviii	85.86 (3)	O1ⁱ—K—F3^xi	142.29 (3)
F5ⁱ—Zr—Zr^xviii	106.09 (3)	O2^x—K—F3^xi	103.01 (3)
F2—Zr—Zr^xviii	104.90 (2)	F6^vi—K—Zr^xi	89.24 (2)
F4—Zr—Zr^xviii	171.25 (2)	F5^vii—K—Zr^xi	28.097 (18)
F1ⁱⁱ—Zr—Zr^xviii	32.85 (2)	F3^viii—K—Zr^xi	93.88 (2)
F1ⁱⁱⁱ—Zr—Zr^xviii	32.60 (2)	F2^ix—K—Zr^xi	93.56 (2)
F3—Zr—K^vii	51.84 (3)	F4^ix—K—Zr^xi	112.72 (2)
F6ⁱ—Zr—K^vii	129.16 (3)	O1ⁱ—K—Zr^xi	151.51 (2)
F5ⁱ—Zr—K^vii	39.43 (3)	O2^x—K—Zr^xi	83.09 (2)
F2—Zr—K^vii	139.29 (3)	F3^xi—K—Zr^xi	29.294 (16)
F4—Zr—K^vii	99.03 (2)	F6^vi—K—Zr^ix	97.85 (2)
F1ⁱⁱ—Zr—K^vii	63.98 (3)	F5^vii—K—Zr^ix	75.428 (19)
F1ⁱⁱⁱ—Zr—K^vii	110.72 (3)	F3^viii—K—Zr^ix	163.11 (2)
Zr^xviii—Zr—K^vii	87.200 (6)	F2^ix—K—Zr^ix	26.431 (17)
F3—Zr—K^xv	92.84 (3)	F4^ix—K—Zr^ix	27.023 (17)
F6ⁱ—Zr—K^xv	90.62 (3)	O1ⁱ—K—Zr^ix	95.67 (2)
F5ⁱ—Zr—K^xv	112.37 (3)	O2^x—K—Zr^ix	93.42 (2)
F2—Zr—K^xv	36.80 (2)	F3^xi—K—Zr^ix	121.99 (2)
F4—Zr—K^xv	37.74 (2)	Zr^xi—K—Zr^ix	102.640 (7)
F1ⁱⁱ—Zr—K^xv	172.94 (3)	F6^vi—K—Zr^xvii	20.660 (19)
F1ⁱⁱⁱ—Zr—K^xv	109.12 (2)	F5^vii—K—Zr^xvii	120.27 (2)
Zr^xviii—Zr—K^xv	141.547 (7)	F3^viii—K—Zr^xvii	67.44 (2)
K^vii—Zr—K^xv	123.004 (4)	F2^ix—K—Zr^xvii	83.04 (2)
F3—Zr—K^vi	148.57 (3)	F4^ix—K—Zr^xvii	121.05 (2)
F6ⁱ—Zr—K^vi	27.86 (3)	O1ⁱ—K—Zr^xvii	89.46 (2)
F5ⁱ—Zr—K^vi	83.54 (3)	O2^x—K—Zr^xvii	157.34 (2)
F2—Zr—K^vi	113.62 (3)	F3^xi—K—Zr^xvii	80.348 (18)
F4—Zr—K^vi	106.63 (3)	Zr^xi—K—Zr^xvii	106.804 (8)
F1ⁱⁱ—Zr—K^vi	57.25 (3)	Zr^ix—K—Zr^xvii	103.843 (7)
F1ⁱⁱⁱ—Zr—K^vi	80.80 (3)	F6^vi—K—Zr^viii	65.81 (2)
Zr^xviii—Zr—K^vi	65.435 (5)	F5^vii—K—Zr^viii	137.16 (2)
K^vii—Zr—K^vi	106.804 (8)	F3^viii—K—Zr^viii	20.89 (2)
K^xv—Zr—K^vi	118.448 (4)	F2^ix—K—Zr^viii	131.81 (2)
F3—Zr—K^xvi	29.95 (3)	F4^ix—K—Zr^viii	137.38 (2)
F6ⁱ—Zr—K^xvi	144.59 (3)	O1ⁱ—K—Zr^viii	63.49 (2)
F5ⁱ—Zr—K^xvi	110.23 (3)	O2^x—K—Zr^viii	107.49 (2)
F2—Zr—K^xvi	79.65 (3)	F3^xi—K—Zr^viii	82.684 (18)
F4—Zr—K^xvi	123.50 (3)	Zr^xi—K—Zr^viii	109.132 (8)
F1ⁱⁱ—Zr—K^xvi	79.97 (3)	Zr^ix—K—Zr^viii	143.549 (10)
F1ⁱⁱⁱ—Zr—K^xvi	56.37 (3)	Zr^xvii—K—Zr^viii	50.252 (5)
Zr^xviii—Zr—K^xvi	64.313 (5)	Ni—O1—K^xii	118.84 (4)
K^vii—Zr—K^xvi	70.868 (8)	Ni—O1—H11	110.3 (17)
K^xv—Zr—K^xvi	100.955 (4)	K^xii—O1—H11	102.4 (18)
K^vi—Zr—K^xvi	129.748 (5)	Ni—O1—H12	111.2 (17)
O1^iv—Ni—O1	180.00 (7)	K^xii—O1—H12	106.2 (17)
O1^iv—Ni—O3^v	91.62 (5)	H11—O1—H12	107 (2)
O1—Ni—O3^v	88.38 (5)	Ni—O2—K^xiii	127.74 (4)
O1^iv—Ni—O3ⁱ	88.38 (5)	Ni—O2—H21	107.6 (17)
O1—Ni—O3ⁱ	91.62 (5)	K^xiii—O2—H21	105.2 (17)
O3^v—Ni—O3ⁱ	180.0	Ni—O2—H22	111.1 (16)
O1^iv—Ni—O2^iv	93.00 (4)	K^xiii—O2—H22	97.1 (15)
O1—Ni—O2^iv	87.00 (4)	H21—O2—H22	106 (2)
O3^v—Ni—O2^iv	90.50 (4)	Ni^xii—O3—H31	124.4 (17)
O3ⁱ—Ni—O2^iv	89.50 (4)	Ni^xii—O3—H32	118.5 (19)
O1^iv—Ni—O2	87.00 (4)	H31—O3—H32	108 (2)
O1—Ni—O2	93.00 (4)	Zr^xiv—F1—Zrⁱⁱⁱ	114.55 (4)
O3^v—Ni—O2	89.50 (4)	Zr—F2—K^xv	116.77 (3)
O3ⁱ—Ni—O2	90.50 (4)	Zr—F3—K^xvi	129.16 (5)
O2^iv—Ni—O2	180.00 (5)	Zr—F3—K^vii	98.87 (4)
F6^vi—K—F5^vii	99.70 (3)	K^xvi—F3—K^vii	107.93 (3)
F6^vi—K—F3^viii	78.70 (3)	Zr—F4—K^xv	115.24 (3)
F5^vii—K—F3^viii	121.39 (3)	Zr^xii—F5—K^xi	112.48 (4)
F6^vi—K—F2^ix	72.85 (3)	Zr^xii—F6—K^xvii	131.48 (4)

Symmetry codes: (i) x, y+1, z; (ii) x−1, y+1, z; (iii) −x, −y+1, −z+1; (iv) −x, −y, −z; (v) −x, −y−1, −z; (vi) −x−1/2, y+1/2, −z+1/2; (vii) −x+1/2, y+1/2, −z+1/2; (viii) x+1/2, −y+3/2, z−1/2; (ix) x+1, y, z; (x) x+1, y+1, z; (xi) −x+1/2, y−1/2, −z+1/2; (xii) x, y−1, z; (xiii) x−1, y−1, z; (xiv) x+1, y−1, z; (xv) x−1, y, z; (xvi) x−1/2, −y+3/2, z+1/2; (xvii) −x−1/2, y−1/2, −z+1/2; (xviii) −x−1, −y+2, −z+1.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1—H11···F1^xi	0.79 (3)	2.94 (2)	3.3300 (14)	112.8 (19)
O1—H11···F2^xix	0.79 (3)	1.92 (3)	2.6877 (14)	164 (2)
O1—H12···F4^xx	0.82 (3)	1.82 (3)	2.6375 (13)	177 (2)
O1—H12···F5^iv	0.82 (3)	2.61 (2)	3.0526 (13)	116 (2)
O2—H21···F1^xi	0.78 (2)	2.59 (2)	3.0048 (13)	115 (2)
O2—H21···F2^xix	0.78 (2)	1.95 (2)	2.7227 (13)	167 (2)
O2—H22···F4^xxi	0.82 (2)	1.92 (2)	2.7362 (13)	173 (2)
O2—H22···F6^xxii	0.82 (2)	2.76 (2)	3.1924 (14)	114.9 (17)
O3—H31···F1^xxiii	0.80 (3)	2.86 (3)	3.2552 (16)	113.3 (19)
O3—H31···F5^xxiv	0.80 (3)	1.92 (3)	2.7019 (14)	168 (2)
O3—H32···F3^iv	0.80 (3)	3.00 (2)	3.4527 (16)	119 (2)
O3—H32···F6^xxv	0.80 (3)	1.97 (3)	2.7427 (15)	163 (2)

Symmetry codes: (iv) −x, −y, −z; (xi) −x+1/2, y−1/2, −z+1/2; (xix) x+1/2, −y+1/2, z−1/2; (xx) −x, −y+1, −z; (xxi) −x−1, −y+1, −z; (xxii) −x−1, −y, −z; (xxiii) x−1/2, −y−1/2, z−1/2; (xxiv) x+1/2, −y−1/2, z−1/2; (xxv) −x−1, −y−1, −z.

Experimental details

Crystal data
Chemical formula	K₂[Ni(H₂O)₆][ZrF₆]₂
M_r	655.45
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	296
a, b, c (Å)	6.6090 (1), 10.0398 (1), 11.7843 (1)
β (°)	95.897 (1)
V (Å³)	777.79 (2)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	3.20
Crystal size (mm)	0.28 × 0.14 × 0.09

Data collection
Diffractometer	Bruker APEXII CCD
Absorption correction	Multi-scan (SADABS; Bruker, 2008)
T_min, T_max	0.613, 0.748
No. of measured, independent and observed [I > 2σ(I)] reflections	17267, 4436, 3858
R_int	0.028
(sin θ/λ)_max (Å⁻¹)	0.882

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.023, 0.052, 1.06
No. of reflections	4436
No. of parameters	131
H-atom treatment	All H-atom parameters refined
Δρ_max, Δρ_min (e Å⁻³)	0.63, −0.57

Computer programs: APEX2 (Bruker, 2008), SAINT (Bruker, 2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg, 1999) and ORTEP-3 for Windows (Farrugia, 1997), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1—H11···F1ⁱ	0.79 (3)	2.94 (2)	3.3300 (14)	112.8 (19)
O1—H11···F2ⁱⁱ	0.79 (3)	1.92 (3)	2.6877 (14)	164 (2)
O1—H12···F4ⁱⁱⁱ	0.82 (3)	1.82 (3)	2.6375 (13)	177 (2)
O1—H12···F5^iv	0.82 (3)	2.61 (2)	3.0526 (13)	116 (2)
O2—H21···F1ⁱ	0.78 (2)	2.59 (2)	3.0048 (13)	115 (2)
O2—H21···F2ⁱⁱ	0.78 (2)	1.95 (2)	2.7227 (13)	167 (2)
O2—H22···F4^v	0.82 (2)	1.92 (2)	2.7362 (13)	173 (2)
O2—H22···F6^vi	0.82 (2)	2.76 (2)	3.1924 (14)	114.9 (17)
O3—H31···F1^vii	0.80 (3)	2.86 (3)	3.2552 (16)	113.3 (19)
O3—H31···F5^viii	0.80 (3)	1.92 (3)	2.7019 (14)	168 (2)
O3—H32···F3^iv	0.80 (3)	3.00 (2)	3.4527 (16)	119 (2)
O3—H32···F6^ix	0.80 (3)	1.97 (3)	2.7427 (15)	163 (2)

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

Comparison of the geometrical characteristics of the coordination polyhedra in isotypic M^I₂[M^II(H₂O)₆][ZrF₆]₂ structures determined from single-crystal data (Å, °, Å³) top

	K₂[Ni(H₂O)₆][ZrF₆]₂^a	K₂[Cu(H₂O)₆][ZrF₆]₂^b	K₂[Zn(H₂O)₆][ZrF₆]₂^c	Cs₂[Zn(H₂O)₆][ZrF₆]₂^d
Space group	P2₁/n	P2₁/c	P2₁/c	P2₁/n
a	6.6090 (1)	6.631 (6)	6.631 (1)	6.970 (1)
b	10.0398 (1)	9.981 (10)	10.071 (1)	10.515 (2)
c	11.7843 (1)	12.921 (12)	12.952 (1)	11.803 (2)
β	95.897 (1)	114.20 (15)	114.96 (2)	93.56 (3)
V	777.786 (16)	780.01 (1)	784.16 (2)	863.4 (3)
	Ni—O1 = 2.0548 (10) (2×)	Cu—O1 = 1.966 (4) (2×)	Zn—O1 = 2.0856 (2) (2×)	Zn—O3 = 2.096 (6) (2×)
Distances M^II—O	Ni—O3 = 2.0570 (11) (2×)	Cu—O2 = 2.025 (6) (2×)	Zn—O2 = 2.0940 (1) (2×)	Zn—O1 = 2.099 (5) (2×)
	Ni—O2 = 2.0781 (9) (2×)	Cu—O3 = 2.327 (5) (2×)	Zn—O3 = 2.1185 (2) (2×)	Zn—O2 = 2.105 (5) (2×)
Average M^II—O bond length	2.063	2.106	2.099	2.100
Polyhedral volume	11.684	12.335	12.318	12.341
Distortion index (bond length)	0.00483	0.06089	0.00607	0.00156
Quadratic elongation	1.0013	1.0124	1.0011	1.0006
	Zr—F6 = 1.9718 (9)	Zr—F3 = 1.968 (5)	Zr—F3 = 1.9727 (3)	Zr—F3 = 1.962 (5)
	Zr—F5 = 2.0006 (8)	Zr—F1 = 2.004 (5)	Zr—F1 = 2.0018 (3)	Zr—F6 = 1.977 (5)
	Zr—F3 = 2.0293 (9)	Zr—F5 = 2.029 (4)	Zr—F5 = 2.0277 (3)	Zr—F5 = 2.037 (5)
Distances Zr—F (Å)	Zr—F2 = 2.0554 (8)	Zr—F6 = 2.059 (4)	Zr—F6 = 2.0570 (3)	Zr—F4 = 2.067 (4)
	Zr—F1 = 2.0708 (8)	Zr—F2 = 2.063 (4)	Zr—F2 = 2.0668 (4)	Zr—F2 = 2.069 (4)
	Zr—F4 = 2.1468 (9)	Zr—F4 = 2.156 (5)	Zr—F4 = 2.1501 (4)	Zr—F1 = 2.156 (4)
	Zr—F4 = 2.1614 (8)	Zr—F4 = 2.160 (4)	Zr—F4 = 2.1628 (4)	Zr—F1 = 2.180 (4)
Average Zr—F bond length	2.062	2.063	2.063	2.064
Polyhedral volume	13.669	13.674	13.675	13.692
Distortion index (bond length)	0.02662	0.02650	0.02654	0.02985
	K—F5 = 2.6496 (10)	K—F1 = 2.668 (5)	K—F1 = 2.6506 (3)	Cs—F6 = 2.911 (5)
	K—F3 = 2.7366 (9)	K—F6 = 2.750 (6)	K—F2 = 2.7395 (4)	Cs—F4 = 3.046 (4)
	K—F6 = 2.7603 (11)	K—F3 = 2.756 (5)	K—F5 = 2.7633 (2)	Cs—F2 = 3.057 (4)
Distances K—F/O	K—F2 = 2.7658 (9)	K—F5 = 2.767 (5)	K—F6 = 2.7739 (2)	Cs—F3 = 3.065 (5)
	K—F1 = 2.7895 (9)	K—F2 = 2.799 (5)	K—F3 = 2.8094 (2)	Cs—F3 = 3.102 (5)
	K—O2 = 2.8927 (10)	K—O3 = 2.942 (5)	K—O1 = 2.8968 (3)	Cs—O2 = 3.218 (5)
	K—O1 = 3.1012 (10)	K—O1 = 2.980 (5)	K—O2 = 3.0873 (5)	Cs—O1 = 3.236 (5)
	K—F6 = 3.1684 (12)	K—F3 = 3.1307 (7)	K—F3 = 3.1707 (7)	Cs—F5 = 3.228 (6)
Average M^I—F/O bond length	2.858	2.849	2.861	3.118
Polyhedral volume	38.458	38.158	38.569	48.130
Distortion index (bond length)	0.05146	0.04429	0.04984	0.02627

Notes: (a) this work; (b) Fischer & Weiss (1973); (c) Bukvetskii et al. (1993); (d) Hitchman et al. (2002).

References

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