A mixed indium–iron lithium diphosphate, In_0.51Fe_0.49LiP₂O₇

The structure of In_0.51Fe_0.49LiP₂O₇ consists of a three-dimensional network constructed from (In^III/Fe^III)O₆ octa­hedra and P₂O₇ groups. Each M^IIIO₆ octa­hedron is linked to six PO₄ tetra­hedra belonging to five different P₂O₇ groups and shares two corners with the same P₂O₇ group so as to build infinite chains or rather parallel colums of [M^IIIP₂O₁₁] running along the a axis. The linkage between these chains or columns defines hepta­gonal tunnels parallel to [100] in which the Li⁺ ions are located in off-centred positions. The In_0.51Fe_0.49LiP₂O₇ compound can be regarded as one composition of the continuous solid solution between LiFeP₂O₇ and LiInP₂O₇ whose structure is isotypic with the A^IFeP₂O₇ (A^I = Na, K, Rb, Cs and Ag) diphosphate family.

Related literature

For physical properties and potential applications of A^IM^IIIP₂O₇ (A^I = Li, Na, K, Rb, Cs and Ag; M^III = Al, Ga, Cr, Fe, In, Y) diphosphates, see: Terebilenko et al. (2010); Hizhnyi et al. (2008); Whangbo et al. (2004); Vitins et al. (2000). For isotypic structures, see: Tran Qui et al. (1987); Rousse et al. (2002). For a closely related structure, see: Zouihri et al. (2011). For background to bond-valence analysis, see: Brown & Altermatt (1985).

Experimental

Crystal data

• In_0.51Fe_0.49LiP₂O₇

• M_r = 267.10

• Monoclinic, P 2₁

• a = 4.8698 (2) Å

• b = 8.2761 (4) Å

• c = 6.9980 (3) Å

• β = 109.650 (2)°

• V = 265.62 (2) ų

• Z = 2

• Mo Kα radiation

• μ = 4.25 mm⁻¹

• T = 296 K

• 0.11 × 0.08 × 0.04 mm

Data collection

• Bruker X8 APEXII CCD area-detector diffractometer

• Absorption correction: multi-scan (SADABS; Sheldrick, 1999) T_min = 0.673, T_max = 0.845

• 13153 measured reflections

• 4262 independent reflections

• 4200 reflections with I > 2σ(I)

• R_int = 0.023

Refinement

• R[F² > 2σ(F²)] = 0.013

• wR(F²) = 0.032

• S = 1.04

• 4262 reflections

• 103 parameters

• 2 restraints

• Δρ_max = 0.74 e Å⁻³

• Δρ_min = −0.55 e Å⁻³

• Absolute structure: Flack (1983), 1965 Friedel pairs

• Flack parameter: 0.021 (6)

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia,1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Supporting information

S1. Comment

As reported in a previous study, physical properties and potential applications of A^IM^IIIP₂O₇ (A^I = Li, Na, K, Rb, Cs and Ag; M^III = Al, Ga, Cr, Fe, In, Y) diphosphates have attracted the interest of several researchers (Zouihri et al. (2011); Terebilenko et al. (2010); Hizhnyi et al. (2008); Whangbo et al. (2004); Vitins et al. (2000)). In this context, the present work reports on the determination of In_0.51Fe_0.49LiP₂O₇ crystal structure from X-ray diffraction single-crystal data.

In an attempt to synthesize an Indium-Iron Lithium Diphosphate, we obtained the following compound of formula: In_0.51Fe_0.49LiP₂O₇. The calculated valences for the mixed site (In/Fe)^III+, Li^I+ and P^V+ ions are as expected, viz. 3.23, 0.91 and 5.0, respectively. A three-dimensional view of the In_0.51Fe_0.49LiP₂O₇ crystal structure along the a axis, is shown in Fig. 1. The structural network of this phosphate is built up from (In/Fe)O₆ (to be noted MO₆) octahedra linked to P₂O₇ diphosphate groups by a corner-sharing. The M^IIIO₆ octahedra are almost regular with homogeneous M^III—O bond lengths ranging from 2.0225 (9) Å to 2.1230 (6) Å. Each MO₆ octahedron is surrounded by six PO₄ tetrahedra belonging to five different P₂O₇ groups and shares two corners with the same P₂O₇ group as shown in Fig.1 and Fig.2. This induces a 3-D framework in which heptagonal channels parallel to [100] direction are formed. The Li⁺ cations are located in the tunnels but in off-centred positions as shown in Fig.2. Although, the coordination sphere of each Li⁺ cation is composed of four O^2- anions located at Li–O distances ranging from 1.956 (3) to 2.107 (3) Å and the fifth at 2.676 (4) Å,in a distorted bi-pyramidal geometry. Furthermore, the diphosphate group exhibits an almost eclipsed conformation with a P–O–P angle of 131.07 (5) °. This value is intermediate between 128.8 (2) ° and 132.7 (4) ° observed for LiFeP₂0₇ and LiInP₂0₇ respectively) (Rousse et al. (2002); Tran Qui et al. (1987). This is not surprising because In_0.51Fe_0.49LiP₂O₇ can be regarded as one composition of the continuous solid solution between LiFeP₂O₇ and LiInP₂O₇ whose structure is isotypic with the A^IM^IIIP₂O₇ (A^I = Li, Na, K, Rb, Cs and Ag; M^III = Al, Sc, Cr, Fe, Ga, Y and In) diphosphates family.

Related literature

For physical properties and potential applications of A^IM^IIIP₂O₇ (A^I = Li, Na, K, Rb, Cs and Ag; M^III = Al, Ga, Cr, Fe, In, Y) diphosphates, see: Terebilenko et al. (2010); Hizhnyi et al. (2008); Whangbo et al. (2004); Vitins et al. (2000). For isotypic structures, see: Tran Qui et al. (1987); Rousse et al. (2002); Zouihri et al. (2011). For background to bond-valence analysis, see: Brown & Altermatt (1985).

S2. Experimental

Single crystals of the title compound, In_0.51Fe_0.49LiP₂O₇ phase, were synthesized by flux methods. Indeed, mixture of 0.0004 mole In2O3, 0.0004 mole Fe₂O₃, and 0.004 mole (NH₄)₂HPO₄ were addided to 0.0008 mole B(OH)₃ and 0.0008 mole LiBO₂ as flux and heated to 1323 K in a platinum crucible. The mixture is lowered to 1223 K with a speed of 0.5°min^-1 and maintained at this temperature for 20 h and then followed by slow cooling to room temperature at a rate of 0.5°min^-1 resulted in colourless crystals of the title compound.

S3. Refinement

The space group is not centro symmetric and the polar axis restraint is generated automatically by Shelxl program. Friedel opposites reflections are not merged. The refinement of the occupancies of the two metal In and Fe and the bond valence sum calculations led to a site occupancy factor of 0.514 (2) for In and 0.486 (2) for Fe. The refinement with a fixed weights (WGHT 0.1) led to a goodness of fit <1 (GooF = S = 0.407). The reflection 002 is omitted because the difference between its calculated and observed intensities is very large. The highest and deepest hole residual peak in the final difference Fourier map are located at 0.60 Å and 0.51 Å, from Fe1.

Computing details

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia,1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

Fig. 1. Partial plot of In0.51Fe0.49LiP2O7 crystal structure shawing plyhedra linkage. Displacement ellipsoids are drawn at the 50% probability level. Symmetry codes: (i) x + 1, y, z; (ii) -x, y - 1/2, -z + 1; (iii) -x, y - 1/2, -z + 2; (iv) -x + 1, y - 1/2, -z + 2; (v) -x, y + 1/2, -z + 1; (vi) x, y, z + 1; (vii) -x, y + 1/2, -z + 2; (viii) -x + 1, y + 1/2, -z + 2; (ix) x + 1, y, z + 1; (x) x - 1, y, z; (xi) x, y, z - 1; (xii) x - 1, y, z - 1.

Fig. 2. Perspective view along [100] of the In0.51Fe0.49LiP2O7 framework structure showing tunnels where lithium cations are located.

indium iron lithium diphosphate

Crystal data

In0.51Fe0.49LiP2O7	F(000) = 254
Mr = 267.10	Dx = 3.340 Mg m^−3
Monoclinic, P21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2yb	Cell parameters from 276 reflections
a = 4.8698 (2) Å	θ = 2.4–34.1°
b = 8.2761 (4) Å	µ = 4.25 mm^−1
c = 6.9980 (3) Å	T = 296 K
β = 109.650 (2)°	Prism, colourless
V = 265.62 (2) Å^3	0.11 × 0.08 × 0.04 mm
Z = 2

Data collection

Bruker X8 APEXII CCD area-detector diffractometer	4262 independent reflections
Radiation source: fine-focus sealed tube	4200 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.023
ω and ϕ scans	θmax = 45.0°, θmin = 3.1°
Absorption correction: multi-scan (SADABS; Sheldrick, 1999)	h = −9→9
Tmin = 0.673, Tmax = 0.845	k = −16→16
13153 measured reflections	l = −6→13

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	w = 1/[σ^2(Fo^2) + (0.0043P)^2] where P = (Fo^2 + 2Fc^2)/3
R[F^2 > 2σ(F^2)] = 0.013	(Δ/σ)max = 0.003
wR(F^2) = 0.032	Δρmax = 0.74 e Å^−3
S = 1.04	Δρmin = −0.55 e Å^−3
4262 reflections	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
103 parameters	Extinction coefficient: 0.0116 (11)
2 restraints	Absolute structure: Flack (1983), 1965 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.021 (6)

Special details

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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)
In1	0.279204 (12)	0.015329 (8)	0.764879 (9)	0.00719 (2)	0.5138 (15)
Fe1	0.279204 (12)	0.015329 (8)	0.764879 (9)	0.00719 (2)	0.4862 (15)
P1	0.10011 (4)	0.33286 (3)	0.97617 (3)	0.00688 (3)
P2	−0.29679 (4)	0.23110 (3)	0.58018 (3)	0.00860 (4)
O1	−0.09909 (15)	0.33270 (9)	1.10229 (11)	0.01212 (10)
O2	0.30388 (14)	0.47713 (8)	1.01372 (10)	0.01034 (9)
O3	0.25898 (14)	0.17252 (8)	0.99381 (10)	0.01044 (9)
O4	−0.56214 (17)	0.19541 (11)	0.63576 (14)	0.01698 (14)
O5	−0.36828 (19)	0.31921 (11)	0.37968 (11)	0.01694 (14)
O6	−0.11997 (18)	0.08092 (10)	0.57623 (14)	0.01796 (13)
O7	−0.09802 (15)	0.35652 (9)	0.74311 (10)	0.01196 (10)
Li1	−0.3013 (6)	0.1486 (3)	0.1793 (4)	0.0222 (4)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
In1	0.00727 (2)	0.00677 (2)	0.00816 (2)	0.00070 (2)	0.00341 (1)	0.00021 (2)
Fe1	0.00727 (2)	0.00677 (2)	0.00816 (2)	0.00070 (2)	0.00341 (1)	0.00021 (2)
P1	0.00698 (6)	0.00674 (7)	0.00732 (7)	−0.00058 (5)	0.00292 (5)	−0.00079 (5)
P2	0.00781 (7)	0.01113 (9)	0.00698 (7)	−0.00074 (6)	0.00265 (5)	−0.00012 (6)
O1	0.0138 (2)	0.0115 (2)	0.0150 (2)	−0.00187 (18)	0.0100 (2)	−0.0021 (2)
O2	0.00973 (19)	0.0089 (2)	0.0116 (2)	−0.00300 (15)	0.00246 (16)	0.00044 (16)
O3	0.0116 (2)	0.0086 (2)	0.0107 (2)	0.00203 (16)	0.00313 (17)	−0.00045 (16)
O4	0.0118 (2)	0.0212 (4)	0.0209 (3)	−0.0004 (2)	0.0093 (2)	0.0037 (3)
O5	0.0205 (3)	0.0217 (4)	0.0069 (2)	−0.0039 (3)	0.0023 (2)	0.0026 (2)
O6	0.0149 (3)	0.0128 (3)	0.0271 (4)	0.0001 (2)	0.0082 (2)	−0.0071 (3)
O7	0.0137 (2)	0.0108 (2)	0.0083 (2)	0.00030 (18)	−0.00045 (17)	−0.00100 (17)
Li1	0.0273 (11)	0.0189 (10)	0.0245 (10)	−0.0051 (8)	0.0140 (8)	−0.0082 (8)

Geometric parameters (Å, º)

In1—O6	2.0225 (9)	P2—O4	1.4988 (8)
In1—O4^i	2.0258 (8)	P2—O5	1.5142 (8)
In1—O5^ii	2.0350 (8)	P2—O6	1.5176 (8)
In1—O3	2.0916 (6)	P2—O7	1.6038 (7)
In1—O1^iii	2.1133 (7)	Li1—O5	2.092 (2)
In1—O2^iv	2.1230 (6)	Li1—O6	2.676 (3)
P1—O1	1.5152 (7)	Li1—O2^ii	1.956 (2)
P1—O2	1.5179 (7)	Li1—O1^v	1.985 (3)
P1—O3	1.5200 (7)	Li1—O3^vi	2.107 (3)
P1—O7	1.6034 (7)
O6—In1—O4^i	86.47 (4)	O2—P1—O7	102.40 (4)
O6—In1—O5^ii	102.03 (3)	O3—P1—O7	107.75 (4)
O4^i—In1—O5^ii	100.84 (3)	O4—P2—O5	112.69 (4)
O6—In1—O3	92.90 (3)	O4—P2—O6	112.79 (5)
O4^i—In1—O3	90.42 (3)	O5—P2—O6	109.43 (5)
O5^ii—In1—O3	161.74 (3)	O4—P2—O7	108.06 (5)
O6—In1—O1^iii	91.67 (3)	O5—P2—O7	104.05 (4)
O4^i—In1—O1^iii	177.82 (3)	O6—P2—O7	109.42 (4)
O5^ii—In1—O1^iii	80.65 (3)	P1—O7—P2	131.07 (5)
O3—In1—O1^iii	88.54 (3)	O2^ii—Li1—O1^v	104.95 (12)
O6—In1—O2^iv	171.79 (3)	O2^ii—Li1—O5	170.56 (15)
O4^i—In1—O2^iv	91.17 (3)	O1^v—Li1—O5	82.36 (10)
O5^ii—In1—O2^iv	86.14 (3)	O2^ii—Li1—O3^vi	82.74 (10)
O3—In1—O2^iv	79.25 (2)	O1^v—Li1—O3^vi	104.76 (14)
O1^iii—In1—O2^iv	90.52 (3)	O5—Li1—O3^vi	89.67 (10)
O1—P1—O2	114.15 (4)	O2^ii—Li1—O6	119.23 (13)
O1—P1—O3	111.10 (4)	O1^v—Li1—O6	114.95 (11)
O2—P1—O3	112.79 (4)	O5—Li1—O6	61.10 (7)
O1—P1—O7	107.97 (4)	O3^vi—Li1—O6	124.85 (11)

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

 

Footnotes

‡Permanant address: Centre National pour la Recherche Scientifique et Technique, Division UATRS, Angle Allal AlFassi et Avenue des FAR, Hay Ryad, BP 8027 Rabat, Morocco.