SrNi₃(P₂O₇)₂

The title compound, strontium trinickel bis­(diphosphate), SrNi₃(P₂O₇)₂, is isostructural with all other mixed metal pyrophosphates having the same stoichiometry. The Sr and one of the Ni ions are located on a crystallographic centre of inversion.

Key indicators

• Single-crystal X-ray study
• T = 173 K
• Mean [sigma](P-O) = 0.001 Å
• R factor = 0.021
• wR factor = 0.054
• Data-to-parameter ratio = 20.0

checkCIF results

No syntax errors found



ADDSYM reports no extra symmetry

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:   Ni3 O14 P4 Sr1
          Atom count from _chemical_formula_moiety:Ni3 O7 P2 Sr1

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S1. Comment

Pyrophosphates are of interest because of their complex network architecture and several structures have been previously determined. The title compound, SrNi₃(P₂O₇)₂, has already been investigated by powder diffraction (El-Bali, 1993), but since its single-crystal structure has not been determined yet, it is presented here.

The Sr and one of the Ni ions are located on a crystallographic centre of inversion. All other atoms occupy general positions. The structure consists of infinite zigzag chains of NiO₆ octahedra sharing either trans or skew edges. These chains are connected by P₂O₇ moieties to form a three-dimensional network into which the Sr ions are incorporated via connections to eight O atoms. The structure of SrNi₃(P₂O₇)₂ is isostructural with all other metal pyrophosphates having the same stoichiometry: Ni₃Pb(P₂O₇)₂ (Krasnikov et al., 1985), CaNi₃(P₂O₇)₂, CaCo₃(P₂O₇)₂ and SrFe₃(P₂O₇)₂ (Lii et al., 1993), and PbCo₃(P₂O₇)₂ and PbFe₃(P₂O₇)₂ (Elmarzouki et al., 1995).

S2. Experimental

A mixture of (NH₄)₂HPO₄, Sr(OH)₂ and NiCl₂ was ground together and heated to approximately 800 K. The molten mass was maintained at this temperature for two days and then cooled down to room temperature (El-Bali, 1993).

Computing details

Data collection: X-AREA (Stoe & Cie, 2001); cell refinement: X-AREA; data reduction: X-AREA; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP in SHELXTL-Plus (Sheldrick, 1991).

Figures

Fig. 1. A perspective view of the title compound with the atom-numbering scheme. Displacement ellipsoids are at the 50% probability level. Symmetry operators: (A) 1 - x, y + 0.5, 0.5 - z; (B) x, 1.5 - y, z - 0.5; (C) x, y + 1, z; (D) 1 - x, 1 - y, z; (E) 1 - x, 2 - y, -z; (F) x - 1, y, z; (G) x - 1, 1.5 - y, 0.5 - z.

Strontium trinickel bis(diphosphate)

Crystal data

SrNi3(P2O7)2	F(000) = 588
Mr = 611.63	Dx = 4.093 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 7.4116 (4) Å	Cell parameters from 39700 reflections
b = 7.6542 (3) Å	θ = 3.8–37.3°
c = 9.4486 (6) Å	µ = 11.69 mm^−1
β = 112.194 (5)°	T = 173 K
V = 496.30 (5) Å^3	Block, yellow
Z = 2	0.24 × 0.18 × 0.16 mm

Data collection

Stoe IPDS II two-circle diffractometer	2076 independent reflections
Radiation source: fine-focus sealed tube	2027 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.052
ω scans	θmax = 34.3°, θmin = 4.0°
Absorption correction: empirical (using intensity measurements) (MULABS; Spek, 1990; Blessing, 1995)	h = −11→11
Tmin = 0.101, Tmax = 0.156	k = −12→10
26742 measured reflections	l = −14→14

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)] = 0.021	w = 1/[σ^2(Fo^2) + (0.0304P)^2 + 0.4865P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.054	(Δ/σ)max = 0.001
S = 1.13	Δρmax = 0.78 e Å^−3
2076 reflections	Δρmin = −0.78 e Å^−3
104 parameters	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.096 (2)

Special details

Experimental. ;

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
Sr1	0.5000	1.0000	0.0000	0.01074 (7)
Ni1	0.18424 (3)	0.62596 (3)	0.02578 (2)	0.00958 (7)
Ni2	0.0000	1.0000	0.0000	0.00934 (7)
P1	0.60256 (6)	0.44098 (5)	0.20097 (4)	0.00920 (8)
P2	0.88811 (6)	0.70400 (5)	0.19372 (4)	0.00911 (8)
O1	0.39757 (18)	0.47873 (17)	0.19242 (14)	0.0113 (2)
O2	0.62427 (18)	0.31912 (17)	0.08281 (14)	0.01178 (19)
O3	0.73161 (18)	0.38239 (16)	0.36484 (14)	0.01116 (19)
O4	0.67992 (17)	0.62943 (16)	0.17742 (14)	0.0112 (2)
O5	0.97336 (18)	0.57480 (16)	0.11291 (14)	0.01094 (19)
O6	0.99820 (18)	0.71065 (16)	0.36620 (13)	0.01111 (19)
O7	0.84443 (18)	0.87709 (16)	0.11085 (14)	0.0112 (2)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Sr1	0.01043 (10)	0.01129 (10)	0.01150 (10)	−0.00001 (6)	0.00528 (7)	0.00012 (6)
Ni1	0.00949 (10)	0.00950 (10)	0.01023 (10)	0.00014 (6)	0.00425 (7)	0.00016 (6)
Ni2	0.00950 (13)	0.00890 (13)	0.01007 (12)	0.00003 (8)	0.00420 (10)	0.00001 (8)
P1	0.00881 (16)	0.00958 (16)	0.00973 (16)	−0.00004 (12)	0.00408 (12)	0.00005 (12)
P2	0.00937 (15)	0.00872 (15)	0.00969 (15)	−0.00011 (12)	0.00413 (12)	0.00005 (12)
O1	0.0095 (4)	0.0126 (5)	0.0128 (5)	0.0006 (4)	0.0051 (4)	0.0010 (4)
O2	0.0124 (5)	0.0120 (5)	0.0119 (4)	−0.0005 (4)	0.0055 (4)	−0.0019 (4)
O3	0.0108 (4)	0.0118 (5)	0.0101 (4)	0.0001 (4)	0.0031 (4)	0.0006 (3)
O4	0.0092 (4)	0.0106 (5)	0.0138 (5)	−0.0014 (4)	0.0046 (4)	0.0005 (4)
O5	0.0118 (5)	0.0103 (4)	0.0120 (4)	0.0001 (4)	0.0059 (4)	−0.0009 (4)
O6	0.0125 (5)	0.0103 (5)	0.0098 (4)	−0.0007 (4)	0.0033 (4)	−0.0004 (3)
O7	0.0116 (5)	0.0104 (5)	0.0125 (4)	0.0004 (4)	0.0055 (4)	0.0013 (4)

Geometric parameters (Å, º)

Sr1—O7	2.5453 (12)	Ni2—O3^vi	2.1164 (12)
Sr1—O7^i	2.5453 (12)	Ni2—Sr1^vii	3.7058 (2)
Sr1—O2^ii	2.6234 (13)	P1—O2	1.5094 (13)
Sr1—O2^iii	2.6234 (13)	P1—O1	1.5184 (13)
Sr1—O3^iv	2.6541 (13)	P1—O3	1.5474 (13)
Sr1—O3^v	2.6541 (13)	P1—O4	1.5985 (13)
Sr1—O1^v	2.7169 (13)	P1—Sr1^viii	3.2230 (4)
Sr1—O1^iv	2.7169 (13)	P2—O7	1.5105 (13)
Sr1—P1^v	3.2229 (4)	P2—O6	1.5231 (12)
Sr1—P1^iv	3.2229 (4)	P2—O5	1.5247 (13)
Sr1—O4^i	3.3083 (12)	P2—O4	1.5971 (13)
Sr1—O4	3.3083 (12)	O1—Sr1^viii	2.7169 (13)
Ni1—O6^vi	2.0415 (12)	O2—Ni1^iii	2.0841 (12)
Ni1—O5^vii	2.0606 (12)	O2—Sr1^ix	2.6234 (13)
Ni1—O5^iii	2.0704 (12)	O3—Ni2^viii	2.1164 (12)
Ni1—O2^iii	2.0841 (12)	O3—Ni1^viii	2.1961 (12)
Ni1—O1	2.0901 (13)	O3—Sr1^viii	2.6541 (13)
Ni1—O3^iv	2.1961 (12)	O5—Ni1^x	2.0606 (12)
Ni2—O6^iv	2.0458 (12)	O5—Ni1^iii	2.0704 (12)
Ni2—O6^vi	2.0458 (12)	O6—Ni1^xi	2.0416 (12)
Ni2—O7^i	2.0552 (12)	O6—Ni2^viii	2.0458 (12)
Ni2—O7^vii	2.0552 (12)	O7—Ni2^x	2.0552 (12)
Ni2—O3^iv	2.1163 (12)
O7—Sr1—O7^i	180.0	O1—Ni1—O3^iv	97.34 (5)
O7—Sr1—O2^ii	92.11 (4)	O6^vi—Ni1—Sr1	75.48 (4)
O7^i—Sr1—O2^ii	87.89 (4)	O5^vii—Ni1—Sr1	138.98 (3)
O7—Sr1—O2^iii	87.89 (4)	O5^iii—Ni1—Sr1	137.70 (3)
O7^i—Sr1—O2^iii	92.11 (4)	O2^iii—Ni1—Sr1	42.18 (3)
O2^ii—Sr1—O2^iii	180.00 (6)	O1—Ni1—Sr1	98.45 (4)
O7—Sr1—O3^iv	114.02 (4)	O3^iv—Ni1—Sr1	43.74 (3)
O7^i—Sr1—O3^iv	65.98 (4)	O6^iv—Ni2—O6^vi	180.0
O2^ii—Sr1—O3^iv	112.97 (4)	O6^iv—Ni2—O7^i	94.60 (5)
O2^iii—Sr1—O3^iv	67.03 (4)	O6^vi—Ni2—O7^i	85.40 (5)
O7—Sr1—O3^v	65.98 (4)	O6^iv—Ni2—O7^vii	85.40 (5)
O7^i—Sr1—O3^v	114.02 (4)	O6^vi—Ni2—O7^vii	94.60 (5)
O2^ii—Sr1—O3^v	67.03 (4)	O7^i—Ni2—O7^vii	180.0
O2^iii—Sr1—O3^v	112.97 (4)	O6^iv—Ni2—O3^iv	100.20 (5)
O3^iv—Sr1—O3^v	180.0	O6^vi—Ni2—O3^iv	79.80 (5)
O7—Sr1—O1^v	107.09 (4)	O7^i—Ni2—O3^iv	85.52 (5)
O7^i—Sr1—O1^v	72.91 (4)	O7^vii—Ni2—O3^iv	94.48 (5)
O2^ii—Sr1—O1^v	100.84 (4)	O6^iv—Ni2—O3^vi	79.80 (5)
O2^iii—Sr1—O1^v	79.16 (4)	O6^vi—Ni2—O3^vi	100.20 (5)
O3^iv—Sr1—O1^v	124.39 (4)	O7^i—Ni2—O3^vi	94.48 (5)
O3^v—Sr1—O1^v	55.61 (4)	O7^vii—Ni2—O3^vi	85.52 (5)
O7—Sr1—O1^iv	72.91 (4)	O3^iv—Ni2—O3^vi	180.00 (7)
O7^i—Sr1—O1^iv	107.09 (4)	O6^iv—Ni2—Sr1	103.11 (3)
O2^ii—Sr1—O1^iv	79.16 (4)	O6^vi—Ni2—Sr1	76.89 (3)
O2^iii—Sr1—O1^iv	100.84 (4)	O7^i—Ni2—Sr1	41.10 (3)
O3^iv—Sr1—O1^iv	55.61 (4)	O7^vii—Ni2—Sr1	138.90 (3)
O3^v—Sr1—O1^iv	124.39 (4)	O3^iv—Ni2—Sr1	44.61 (3)
O1^v—Sr1—O1^iv	180.0	O3^vi—Ni2—Sr1	135.39 (3)
O7—Sr1—P1^v	83.14 (3)	O6^iv—Ni2—Sr1^vii	76.89 (3)
O7^i—Sr1—P1^v	96.86 (3)	O6^vi—Ni2—Sr1^vii	103.11 (3)
O2^ii—Sr1—P1^v	87.62 (3)	O7^i—Ni2—Sr1^vii	138.90 (3)
O2^iii—Sr1—P1^v	92.38 (3)	O7^vii—Ni2—Sr1^vii	41.10 (3)
O3^iv—Sr1—P1^v	151.52 (3)	O3^iv—Ni2—Sr1^vii	135.40 (3)
O3^v—Sr1—P1^v	28.48 (3)	O3^vi—Ni2—Sr1^vii	44.61 (3)
O1^v—Sr1—P1^v	28.00 (3)	Sr1—Ni2—Sr1^vii	180.0
O1^iv—Sr1—P1^v	152.00 (3)	O2—P1—O1	117.54 (7)
O7—Sr1—P1^iv	96.86 (3)	O2—P1—O3	111.27 (7)
O7^i—Sr1—P1^iv	83.14 (3)	O1—P1—O3	109.65 (7)
O2^ii—Sr1—P1^iv	92.38 (3)	O2—P1—O4	108.09 (7)
O2^iii—Sr1—P1^iv	87.62 (3)	O1—P1—O4	103.01 (7)
O3^iv—Sr1—P1^iv	28.48 (3)	O3—P1—O4	106.39 (7)
O3^v—Sr1—P1^iv	151.52 (3)	O2—P1—Sr1^viii	149.48 (5)
O1^v—Sr1—P1^iv	152.00 (3)	O1—P1—Sr1^viii	57.14 (5)
O1^iv—Sr1—P1^iv	28.00 (3)	O3—P1—Sr1^viii	54.89 (5)
P1^v—Sr1—P1^iv	180.0	O4—P1—Sr1^viii	102.20 (5)
O7—Sr1—O4^i	132.46 (3)	O7—P2—O6	116.65 (7)
O7^i—Sr1—O4^i	47.54 (3)	O7—P2—O5	110.95 (7)
O2^ii—Sr1—O4^i	51.81 (3)	O6—P2—O5	113.68 (7)
O2^iii—Sr1—O4^i	128.19 (3)	O7—P2—O4	104.68 (7)
O3^iv—Sr1—O4^i	108.93 (3)	O6—P2—O4	102.87 (7)
O3^v—Sr1—O4^i	71.07 (3)	O5—P2—O4	106.73 (7)
O1^v—Sr1—O4^i	60.68 (3)	O7—P2—Sr1	37.37 (5)
O1^iv—Sr1—O4^i	119.32 (3)	O6—P2—Sr1	121.93 (5)
P1^v—Sr1—O4^i	67.61 (2)	O5—P2—Sr1	124.07 (5)
P1^iv—Sr1—O4^i	112.39 (2)	O4—P2—Sr1	67.41 (5)
O7—Sr1—O4	47.54 (3)	P1—O1—Ni1	126.85 (7)
O7^i—Sr1—O4	132.46 (3)	P1—O1—Sr1^viii	94.87 (6)
O2^ii—Sr1—O4	128.19 (3)	Ni1—O1—Sr1^viii	126.85 (5)
O2^iii—Sr1—O4	51.81 (3)	P1—O2—Ni1^iii	121.48 (7)
O3^iv—Sr1—O4	71.07 (3)	P1—O2—Sr1^ix	132.26 (7)
O3^v—Sr1—O4	108.93 (3)	Ni1^iii—O2—Sr1^ix	105.58 (5)
O1^v—Sr1—O4	119.32 (3)	P1—O3—Ni2^viii	124.43 (7)
O1^iv—Sr1—O4	60.68 (3)	P1—O3—Ni1^viii	133.49 (7)
P1^v—Sr1—O4	112.39 (2)	Ni2^viii—O3—Ni1^viii	93.50 (5)
P1^iv—Sr1—O4	67.61 (2)	P1—O3—Sr1^viii	96.63 (6)
O4^i—Sr1—O4	180.00 (4)	Ni2^viii—O3—Sr1^viii	101.34 (5)
O6^vi—Ni1—O5^vii	90.51 (5)	Ni1^viii—O3—Sr1^viii	101.36 (5)
O6^vi—Ni1—O5^iii	85.70 (5)	P2—O4—P1	133.89 (8)
O5^vii—Ni1—O5^iii	77.30 (5)	P2—O4—Sr1	86.12 (5)
O6^vi—Ni1—O2^iii	84.75 (5)	P1—O4—Sr1	138.34 (6)
O5^vii—Ni1—O2^iii	174.47 (5)	P2—O5—Ni1^x	126.67 (7)
O5^iii—Ni1—O2^iii	99.46 (5)	P2—O5—Ni1^iii	123.84 (7)
O6^vi—Ni1—O1	173.91 (5)	Ni1^x—O5—Ni1^iii	102.70 (5)
O5^vii—Ni1—O1	93.94 (5)	P2—O6—Ni1^xi	138.60 (8)
O5^iii—Ni1—O1	99.32 (5)	P2—O6—Ni2^viii	120.71 (7)
O2^iii—Ni1—O1	91.01 (5)	Ni1^xi—O6—Ni2^viii	100.46 (5)
O6^vi—Ni1—O3^iv	78.03 (5)	P2—O7—Ni2^x	127.88 (7)
O5^vii—Ni1—O3^iv	96.04 (5)	P2—O7—Sr1	121.52 (7)
O5^iii—Ni1—O3^iv	162.42 (5)	Ni2^x—O7—Sr1	106.84 (5)
O2^iii—Ni1—O3^iv	85.77 (5)

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