Ni2Si(P2O7)2

Toubi, Y.; Essehli, R.; Dušek, M.; Fejfarová, K.; El Bali, B.

doi:10.1107/S1600536809021734

inorganic compounds

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ISSN: 2056-9890

Volume 65| Part 7| July 2009| Page i55

doi:10.1107/S1600536809021734

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Ni₂Si(P₂O₇)₂

Yahya Toubi,^a Rachid Essehli,^a Michal Dušek,^b Karla Fejfarová ^b and Brahim El Bali ^a ^*

^aLaboratory of Mineral Solid and Analytical Chemistry, "LCSMA", Department of Chemistry, Faculty of Sciences, University Mohamed I, PO Box 717, 60000 Oujda, Morocco, and ^bInstitute of Physics of the ASCR, Na Slovance 2, 182 21 Praha 8, Czech Republic
^*Correspondence e-mail: belbali@fso.ump.ma

(Received 7 May 2009; accepted 8 June 2009; online 27 June 2009)

Dinickel(II) silicon bis[diphosphate(4−)], Ni₂Si(P₂O₇)₂, is isotypic with other phosphates of the formula M₂Si(P₂O₇)₂ (M = Co, Cd). All atoms except Si (site symmetry 2) are found in general positions. Ni₂O₁₀ dimers formed from edge-sharing NiO₆ octahedra are linked by corners and O—P—O bridges, forming slabs parallel to (100), which are in turn interconnected by O—Si—O contacts.

Related literature

For the structures of isotypic compounds, see: Glaum & Schmidt (1996 ) for Co₂Si(P₂O₇)₂ and Trojan et al. (1987 ) for Cd₂Si(P₂O₇)₂. For bond-length and angle data, see: Bostroem (1987 ); Durif (1995 ). For the extinction correction, see: Becker & Coppens (1974 ).

Experimental

Crystal data

Ni₂Si(P₂O₇)₂
M_r = 493.3
Monoclinic, C 2/c
a = 16.8615 (9) Å
b = 4.8948 (2) Å
c = 12.1925 (5) Å
β = 103.693 (4)°
V = 977.69 (8) Å³
Z = 4
Mo Kα radiation
μ = 4.72 mm⁻¹
T = 295 K
0.27 × 0.16 × 0.07 mm

Data collection

Oxford Diffraction Xcalibur diffractometer with Atlas (Gemini ultra Cu) detector
Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2006 $[Oxford Diffraction (2006). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Abingdon, England.]$ ) T_min = 0.438, T_max = 0.829
4978 measured reflections
1013 independent reflections
877 reflections with I > 3σ(I)
R_int = 0.023

Refinement

R[F² > 2σ(F²)] = 0.016
wR(F²) = 0.045
S = 1.34
1013 reflections
97 parameters
Δρ_max = 0.22 e Å⁻³
Δρ_min = −0.23 e Å⁻³

Table 1
Selected bond lengths (Å)

Ni1—O1	1.9631 (18)
Ni1—O4ⁱ	2.2351 (17)
Ni1—O4ⁱⁱ	2.1436 (14)
Ni1—O5ⁱⁱⁱ	2.1271 (17)
Ni1—O5^iv	2.1509 (14)
Ni1—O6	1.9660 (18)
Si1—O2^v	1.6018 (18)
Si1—O2^vi	1.6018 (18)
Si1—O7	1.5881 (16)
Si1—O7^vii	1.5881 (16)
P1—O1	1.4759 (17)
P1—O2	1.564 (2)
P1—O3^viii	1.5888 (15)
P1—O4	1.5132 (16)
P2—O3	1.5873 (19)
P2—O5	1.5017 (17)
P2—O6	1.4768 (18)
P2—O7	1.5458 (16)
Symmetry codes: (i) x, y+1, z; (ii) $[-x+{\script{1\over 2}}, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (iii) x, y-1, z; (iv) $[-x+{\script{1\over 2}}, -y+{\script{3\over 2}}, -z]$ ; (v) $[x+{\script{1\over 2}}, y+{\script{3\over 2}}, z]$ ; (vi) $[-x+{\script{1\over 2}}, y+{\script{3\over 2}}, -z+{\script{1\over 2}}]$ ; (vii) $[-x+1, y, -z+{\script{1\over 2}}]$ ; (viii) $[-x+{\script{1\over 2}}, -y+{\script{1\over 2}}, -z]$ .

Data collection: CrysAlis CCD (Oxford Diffraction, 2006 $[Oxford Diffraction (2006). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Abingdon, England.]$ ); cell refinement: CrysAlis RED (Oxford Diffraction, 2006 $[Oxford Diffraction (2006). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Abingdon, England.]$ ); data reduction: CrysAlis RED; program(s) used to solve structure: Superflip (Palatinus & Chapuis, 2007 ); program(s) used to refine structure: JANA2006 (Petříček et al., 2006 ); molecular graphics: DIAMOND (Brandenburg & Putz, 2005 ); software used to prepare material for publication: JANA2006.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809021734/mg2073sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809021734/mg2073Isup2.hkl

checkCIF report

Comment top

Although the isostructural silicodiphosphates M₂Si(P₂O₇)₂ have been reported for M = Fe, Ni, Co, Cu, and Cd, full single-crystal structure determinations have been carried out only for the Co and Cd members (Glaum & Schmidt, 1996; Trojan et al., 1987). The structure of Ni₂Si(P₂O₇)₂ is reported herein. Its cell parameters are consistent with those obtained earlier from Guinier photographs (Glaum & Schmidt, 1996). The three-dimensional framework is built up of NiO₆ octahedra, SiO₄ tetrahedra, and P₂O₇ diphosphate groups. Ni₂O₁₀ dimers, formed from pairs of edge-sharing NiO₆ octahedra, are interconnected through corners (O4) and O–P–O bridges of the diphosphate groups to generate slabs that lie parallel to (100) (Fig. 1). Neighboring slabs are connected through O–Si–O linkages from the SiO₄ groups (Fig. 2). The NiO₆ octahedron, whose apices are formed from one bidentate and four monodentate P₂O₇ groups (Fig. 3), is strongly distorted, with an average Ni–O distance [2.098 (2) Å] that is between those in Ni₂P₂O₇ (2.114 Å) and Ni₂SiO₄ (2.080 Å) (Bostroem, 1987). The P₂O₇ group adopts a nearly eclipsed conformation, with an average P–O distance [1.532 (2) Å] that is similar to other diphosphates (Durif, 1995) and a rather small P–O–P angle [132.51 (12) °] owing to its bidentate coordination to the Ni center.

Related literature top

For the structures of related compounds, see: Glaum & Schmidt (1996) for Co₂Si(P₂O₇)₂ and Trojan et al. (1987) for Cd₂Si(P₂O₇)₂. For bond-length and angle data, see: Bostroem (1987); Durif (1995).the extinction correction, see: Becker & Coppens (1974).

Experimental top

Ni₂Si(P₂O₇)₂ in the form of powder was prepared by stoichiometric reaction of SiO₂ (99.9%, Aldrich) and Ni₂P₄O₁₂ (the latter being obtained from a reaction of NiO and NH₄H₂PO₄ in a 2:4 ratio at 750 °C for 24 h under O₂ atmosphere). The mixture was heated at 500 °C under Ar atmosphere for 2 days and 700 °C for 36 h with intermediate grindings to ensure complete reaction. Subsequent melting at 1300 °C followed by slow cooling to room temperature at a rate of 5 ° h^-1 resulted in green crystals of the title compound.

Computing details top

Data collection: CrysAlis CCD (Oxford Diffraction, 2006); cell refinement: CrysAlis RED (Oxford Diffraction, 2006); data reduction: CrysAlis RED (Oxford Diffraction, 2006); program(s) used to solve structure: Superflip (Palatinus & Chapuis, 2007); program(s) used to refine structure: JANA2006 (Petříček et al., 2006); molecular graphics: DIAMOND (Brandenburg & Putz, 2005); software used to prepare material for publication: JANA2006 (Petříček et al., 2006).

Figures top

	Fig. 1. Ni₂O₁₀ dimers and their connection in Ni₂Si(P₂O₇)₂.
	Fig. 2. Projection of Ni₂Si(P₂O₇)₂ along [010].
	Fig. 3. Local coordination geometry around the Ni atom in Ni₂Si(P₂O₇)₂. Symmetry codes: (i) x, 1 + y, z, (iii) x, 1 - y, z (ii) -x + 1/2,y + 1/2,-z + 1/2, (iv) -x + 1/2,-y + 3/2,-z, (v) -x + 1/2,-y + 1/2,-z. Displacement ellipsoids are drawn at the 50% probability level.

dinickel(II) silicon bis[diphosphate(4-)] top

Crystal data top

Ni₂Si(P₂O₇)₂	F(000) = 968
M_r = 493.3	D_x = 3.351 Mg m⁻³
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 3598 reflections
a = 16.8615 (9) Å	θ = 2.7–26.5°
b = 4.8948 (2) Å	µ = 4.72 mm⁻¹
c = 12.1925 (5) Å	T = 295 K
β = 103.693 (4)°	Plate, yellow
V = 977.69 (8) Å³	0.27 × 0.16 × 0.07 mm
Z = 4

Data collection top

Oxford Diffraction Xcalibur diffractometer with Atlas (Gemini ultra Cu) detector	1013 independent reflections
Radiation source: fine-focus sealed tube	877 reflections with I > 3σ(I)
Graphite monochromator	R_int = 0.023
Detector resolution: 20.7567 pixels mm^-1	θ_max = 26.5°, θ_min = 3.4°
Rotation method data acquisition using ω scans	h = −20→20
Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2006)	k = −6→6
T_min = 0.438, T_max = 0.829	l = −15→15
4978 measured reflections

Refinement top

Refinement on F²	0 constraints
R[F² > 2σ(F²)] = 0.016	Weighting scheme based on measured s.u.'s w = 1/[σ²(I) + 0.0004I²]
wR(F²) = 0.045	(Δ/σ)_max = 0.010
S = 1.34	Δρ_max = 0.22 e Å⁻³
1013 reflections	Δρ_min = −0.23 e Å⁻³
97 parameters	Extinction correction: B–C type 1 Lorentzian isotropic (Becker & Coppens, 1974)
0 restraints	Extinction coefficient: 370 (80)

Crystal data top

Ni₂Si(P₂O₇)₂	V = 977.69 (8) Å³
M_r = 493.3	Z = 4
Monoclinic, C2/c	Mo Kα radiation
a = 16.8615 (9) Å	µ = 4.72 mm⁻¹
b = 4.8948 (2) Å	T = 295 K
c = 12.1925 (5) Å	0.27 × 0.16 × 0.07 mm
β = 103.693 (4)°

Data collection top

Oxford Diffraction Xcalibur diffractometer with Atlas (Gemini ultra Cu) detector	1013 independent reflections
Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2006)	877 reflections with I > 3σ(I)
T_min = 0.438, T_max = 0.829	R_int = 0.023
4978 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.016	97 parameters
wR(F²) = 0.045	0 restraints
S = 1.34	Δρ_max = 0.22 e Å⁻³
1013 reflections	Δρ_min = −0.23 e Å⁻³

Special details top

Experimental. Absorption correction CrysAlisPro; Oxford Diffraction, 2009; Version 1.171.33.34d (release 27-02-2009 CrysAlis171.NET) Absorption correction: analytical, implemented in CrysAlis RED (Oxford Diffraction, 2006).

Refinement. The refinement was carried out against all reflections. The conventional R-factor is always based on F. The goodness of fit as well as the weighted R-factor are based on F and F² for refinement carried out on F and F², respectively. The threshold expression is used only for calculating R-factors etc. and it is not relevant to the choice of reflections for refinement.

The program used for refinement, Jana2006, uses the weighting scheme based on the experimental expectations, see _refine_ls_weighting_details, that does not force S to be one. Therefore the values of S are usually larger than the ones from the SHELX program.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Ni1	0.247526 (19)	0.35079 (6)	0.12916 (2)	0.00715 (11)
Si1	0.5	1.16111 (18)	0.25	0.0054 (3)
P1	0.12621 (4)	−0.13090 (12)	0.13612 (5)	0.00608 (18)
P2	0.36378 (4)	0.83352 (12)	0.08433 (5)	0.00583 (18)
O1	0.14379 (10)	0.1598 (3)	0.12002 (13)	0.0100 (5)
O2	0.04526 (11)	−0.1475 (3)	0.17733 (12)	0.0088 (5)
O3	0.40484 (11)	0.7811 (3)	−0.01825 (12)	0.0091 (5)
O4	0.19424 (10)	−0.3018 (3)	0.20675 (12)	0.0088 (5)
O5	0.29494 (10)	1.0316 (3)	0.04486 (12)	0.0091 (5)
O6	0.34569 (10)	0.5703 (3)	0.13237 (12)	0.0101 (5)
O7	0.43615 (10)	0.9697 (3)	0.16829 (13)	0.0116 (5)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Ni1	0.00662 (18)	0.00720 (17)	0.00757 (17)	−0.00117 (13)	0.00154 (12)	0.00048 (11)
Si1	0.0046 (5)	0.0065 (4)	0.0053 (4)	0	0.0012 (3)	0
P1	0.0054 (3)	0.0070 (3)	0.0061 (3)	−0.0008 (2)	0.0019 (2)	−0.0002 (2)
P2	0.0055 (3)	0.0064 (3)	0.0054 (3)	−0.0008 (2)	0.0010 (2)	−0.0003 (2)
O1	0.0076 (9)	0.0082 (8)	0.0146 (8)	−0.0006 (7)	0.0035 (7)	0.0012 (7)
O2	0.0085 (9)	0.0103 (8)	0.0088 (7)	−0.0003 (7)	0.0045 (6)	0.0001 (6)
O3	0.0086 (9)	0.0128 (9)	0.0066 (7)	−0.0004 (7)	0.0030 (6)	−0.0013 (6)
O4	0.0079 (9)	0.0094 (8)	0.0085 (8)	0.0019 (7)	0.0009 (7)	−0.0009 (6)
O5	0.0091 (9)	0.0098 (8)	0.0081 (7)	0.0015 (7)	0.0015 (6)	−0.0008 (7)
O6	0.0090 (9)	0.0099 (8)	0.0112 (8)	−0.0022 (7)	0.0019 (7)	0.0025 (6)
O7	0.0092 (10)	0.0145 (9)	0.0099 (8)	−0.0035 (7)	−0.0002 (7)	−0.0037 (7)

Geometric parameters (Å, º) top

Ni1—O1	1.9631 (18)	Si1—O7^vii	1.5881 (16)
Ni1—O4ⁱ	2.2351 (17)	P1—O1	1.4759 (17)
Ni1—O4ⁱⁱ	2.1436 (14)	P1—O2	1.564 (2)
Ni1—O5ⁱⁱⁱ	2.1271 (17)	P1—O3^viii	1.5888 (15)
Ni1—O5^iv	2.1509 (14)	P1—O4	1.5132 (16)
Ni1—O6	1.9660 (18)	P2—O3	1.5873 (19)
Si1—O2^v	1.6018 (18)	P2—O5	1.5017 (17)
Si1—O2^vi	1.6018 (18)	P2—O6	1.4768 (18)
Si1—O7	1.5881 (16)	P2—O7	1.5458 (16)

O1—Ni1—O4ⁱ	86.81 (7)	O2^vi—Si1—O7	110.56 (9)
O1—Ni1—O4ⁱⁱ	95.28 (6)	O2^vi—Si1—O7^vii	109.83 (8)
O1—Ni1—O5ⁱⁱⁱ	93.12 (7)	O7—Si1—O7^vii	107.67 (10)
O1—Ni1—O5^iv	89.28 (6)	O1—P1—O2	108.10 (10)
O1—Ni1—O6	174.93 (7)	O1—P1—O3^viii	111.07 (9)
O4ⁱ—Ni1—O4ⁱⁱ	90.65 (6)	O1—P1—O4	117.37 (9)
O4ⁱ—Ni1—O5ⁱⁱⁱ	176.27 (5)	O2—P1—O3^viii	98.09 (9)
O4ⁱ—Ni1—O5^iv	98.09 (6)	O2—P1—O4	112.97 (9)
O4ⁱ—Ni1—O6	89.81 (7)	O3^viii—P1—O4	107.57 (9)
O4ⁱⁱ—Ni1—O5ⁱⁱⁱ	93.07 (6)	O3—P2—O5	107.46 (9)
O4ⁱⁱ—Ni1—O5^iv	170.37 (7)	O3—P2—O6	109.95 (10)
O4ⁱⁱ—Ni1—O6	88.53 (6)	O3—P2—O7	99.69 (9)
O5ⁱⁱⁱ—Ni1—O5^iv	78.19 (6)	O5—P2—O6	118.30 (10)
O5ⁱⁱⁱ—Ni1—O6	90	O5—P2—O7	111.28 (9)
O5^iv—Ni1—O6	87.45 (6)	O6—P2—O7	108.55 (9)
O2^v—Si1—O2^vi	108.39 (10)	Si1^ix—O2—P1	140.73 (11)
O2^v—Si1—O7	109.83 (8)	P1^viii—O3—P2	132.51 (12)
O2^v—Si1—O7^vii	110.56 (9)	Si1—O7—P2	168.95 (12)

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

Experimental details

Crystal data
Chemical formula	Ni₂Si(P₂O₇)₂
M_r	493.3
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	295
a, b, c (Å)	16.8615 (9), 4.8948 (2), 12.1925 (5)
β (°)	103.693 (4)
V (Å³)	977.69 (8)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	4.72
Crystal size (mm)	0.27 × 0.16 × 0.07

Data collection
Diffractometer	Oxford Diffraction Xcalibur diffractometer with Atlas (Gemini ultra Cu) detector
Absorption correction	Analytical (CrysAlis RED; Oxford Diffraction, 2006)
T_min, T_max	0.438, 0.829
No. of measured, independent and observed [I > 3σ(I)] reflections	4978, 1013, 877
R_int	0.023
(sin θ/λ)_max (Å⁻¹)	0.627

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.016, 0.045, 1.34
No. of reflections	1013
No. of parameters	97
Δρ_max, Δρ_min (e Å⁻³)	0.22, −0.23

Computer programs: CrysAlis CCD (Oxford Diffraction, 2006), CrysAlis RED (Oxford Diffraction, 2006), Superflip (Palatinus & Chapuis, 2007), JANA2006 (Petříček et al., 2006), DIAMOND (Brandenburg & Putz, 2005).

Selected bond lengths (Å) top

Ni1—O1	1.9631 (18)	Si1—O7^vii	1.5881 (16)
Ni1—O4ⁱ	2.2351 (17)	P1—O1	1.4759 (17)
Ni1—O4ⁱⁱ	2.1436 (14)	P1—O2	1.564 (2)
Ni1—O5ⁱⁱⁱ	2.1271 (17)	P1—O3^viii	1.5888 (15)
Ni1—O5^iv	2.1509 (14)	P1—O4	1.5132 (16)
Ni1—O6	1.9660 (18)	P2—O3	1.5873 (19)
Si1—O2^v	1.6018 (18)	P2—O5	1.5017 (17)
Si1—O2^vi	1.6018 (18)	P2—O6	1.4768 (18)
Si1—O7	1.5881 (16)	P2—O7	1.5458 (16)

Acknowledgements

We thank the Grant Agency of the Czech Republic (grant No. 202/06/0757) for support.

References

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