β-Li0.37Na0.63Fe(MoO4)2.

The title compound, lithium/sodium iron(III) bis-[ortho-molyb-date(VI)], was obtained by a solid-state reaction. The main structure units are an FeO6 octa-hedron, a distorted MoO6 octa-hedron and an MoO4 tetra-hedron sharing corners. The crystal structure is composed of infinite double MoFeO11 chains along the b-axis direction linked by corner-sharing to MoO4 tetra-hedra so as to form Fe2Mo3O19 ribbons. The cohesion between ribbons via mixed Mo-O-Fe bridges leads to layers arranged parallel to the bc plane. Adjacent layers are linked by corners shared between MoO4 tetra-hedra of one layer and FeO6 octa-hedra of the other layer. The Na(+) and Li(+) ions partially occupy the same general position, with a site-occupancy ratio of 0.631 (9):0.369 (1). A comparison is made with AFe(MoO4)2 (A = Li, Na, K and Cs) structures.

Related literature

For the electrochemical performance of similar materials, see: Padhi et al. (1997 ▶); Prakash et al. (2000 ▶); Okuyama et al. (2001 ▶); Croce et al. (2003 ▶). For their physical properties, see: Nagpure et al. (2010 ▶); Prasad & Varma (1994 ▶); Chen et al. (2009 ▶); Tomohiro et al. (2002 ▶). For related structures, see: van der Lee et al. (2008 ▶); Klevtsova (1975 ▶); Baza­rov et al. (2010 ▶). For bond-valence parameters, see: Brown & Altermatt, (1985 ▶).

Experimental

Crystal data

Li0.37Na0.63Fe(MoO4)2

M = 392.78

Triclinic,

a = 6.8860 (8) Å

b = 7.2560 (9) Å

c = 7.3786 (9) Å

α = 91.060 (6)°

β = 110.933 (9)°

γ = 105.661 (9)°

V = 328.83 (7) Å3

Z = 2

Mo Kα radiation

μ = 5.98 mm−1

T = 298 K

0.28 × 0.21 × 0.14 mm

Data collection

Enraf-Nonius CAD-4 diffractometer

Absorption correction: ψ scan (North et al., 1968 ▶) T min = 0.286, T max = 0.488

2838 measured reflections

1431 independent reflections

1380 reflections with I > 2σ(I)

R int = 0.015

2 standard reflections every 120 min intensity decay: 1.3%

Refinement

R[F 2 > 2σ(F 2)] = 0.020

wR(F 2) = 0.051

S = 1.19

1431 reflections

112 parameters

Δρmax = 1.23 e Å−3

Δρmin = −0.58 e Å−3

Data collection: CAD-4 EXPRESS (Duisenberg, 1992 ▶; Macíček & Yordanov, 1992 ▶); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo, 1995 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND (Brandenburg & Putz, 1999 ▶); software used to prepare material for publication: WinGX (Farrugia, 2012 ▶).

Crystal structure: contains datablock(s) I. DOI: 10.1107/S1600536814000646/vn2079sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536814000646/vn2079Isup2.hkl

CCDC reference:

Additional supporting information: crystallographic information; 3D view; checkCIF report

Li0.37Na0.63Fe(MoO4)2	Z = 2
Mr = 392.78	F(000) = 364
Triclinic, P1	Dx = 3.967 Mg m−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 6.8860 (8) Å	Cell parameters from 25 reflections
b = 7.2560 (9) Å	θ = 11–15°
c = 7.3786 (9) Å	µ = 5.98 mm−1
α = 91.060 (6)°	T = 298 K
β = 110.933 (9)°	Prism, green
γ = 105.661 (9)°	0.28 × 0.21 × 0.14 mm
V = 328.83 (7) Å3

Enraf-Nonius CAD-4 diffractometer	1380 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.015
Graphite monochromator	θmax = 27.0°, θmin = 2.9°
ω/2θ scans	h = −8→8
Absorption correction: ψ scan (North et al., 1968)	k = −9→9
Tmin = 0.286, Tmax = 0.488	l = −9→9
2838 measured reflections	2 standard reflections every 120 min
1431 independent reflections	intensity decay: 1.3%

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.020	w = 1/[σ2(Fo2) + (0.021P)2 + 0.8764P] where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.051	(Δ/σ)max < 0.001
S = 1.19	Δρmax = 1.23 e Å−3
1431 reflections	Δρmin = −0.58 e Å−3
112 parameters	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
0 restraints	Extinction coefficient: 0.0119 (9)

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.

	x	y	z	Uiso*/Ueq	Occ. (<1)
Mo1	0.18308 (4)	0.03418 (4)	0.28342 (4)	0.00999 (11)
Mo2	0.66625 (5)	0.42440 (4)	0.20010 (5)	0.01552 (11)
Fe1	0.39452 (8)	0.09553 (7)	0.81999 (7)	0.00988 (13)
Na1	0.7648 (4)	0.4490 (3)	0.7567 (4)	0.0221 (8)	0.631 (9)
Li1	0.7648 (4)	0.4490 (3)	0.7567 (4)	0.0221 (8)	0.369 (9)
O1	0.3163 (4)	0.8758 (3)	0.2278 (4)	0.0137 (5)
O2	0.8946 (4)	0.9550 (4)	0.1547 (4)	0.0145 (5)
O3	0.5285 (4)	0.6200 (3)	0.1475 (4)	0.0171 (5)
O4	0.7530 (5)	0.4334 (4)	0.4476 (4)	0.0267 (6)
O5	0.2937 (4)	0.2661 (4)	0.2401 (4)	0.0203 (6)
O6	0.2403 (4)	0.0424 (4)	0.5373 (4)	0.0205 (6)
O7	0.8963 (5)	0.5147 (4)	0.1521 (5)	0.0284 (7)
O8	0.5823 (4)	0.1597 (3)	0.1114 (3)	0.0118 (5)

	U11	U22	U33	U12	U13	U23
Mo1	0.00649 (16)	0.01197 (16)	0.01053 (16)	0.00259 (11)	0.00226 (11)	−0.00055 (10)
Mo2	0.01547 (17)	0.00794 (16)	0.01610 (17)	0.00378 (12)	−0.00234 (12)	−0.00076 (11)
Fe1	0.0090 (2)	0.0088 (2)	0.0107 (2)	0.00255 (17)	0.00243 (18)	0.00021 (17)
Na1	0.0196 (12)	0.0174 (12)	0.0338 (14)	0.0070 (9)	0.0138 (10)	0.0076 (9)
Li1	0.0196 (12)	0.0174 (12)	0.0338 (14)	0.0070 (9)	0.0138 (10)	0.0076 (9)
O1	0.0108 (11)	0.0136 (12)	0.0192 (13)	0.0043 (9)	0.0079 (10)	0.0032 (10)
O2	0.0079 (11)	0.0197 (13)	0.0160 (12)	0.0042 (9)	0.0046 (9)	−0.0008 (10)
O3	0.0194 (13)	0.0091 (11)	0.0184 (13)	0.0053 (10)	0.0015 (10)	−0.0009 (9)
O4	0.0291 (15)	0.0247 (15)	0.0164 (14)	0.0096 (12)	−0.0039 (11)	−0.0030 (11)
O5	0.0191 (13)	0.0144 (12)	0.0253 (14)	0.0021 (10)	0.0080 (11)	−0.0002 (11)
O6	0.0158 (13)	0.0329 (15)	0.0112 (12)	0.0074 (11)	0.0034 (10)	−0.0008 (11)
O7	0.0238 (15)	0.0207 (14)	0.0334 (17)	0.0006 (12)	0.0069 (13)	0.0042 (12)
O8	0.0124 (11)	0.0097 (11)	0.0119 (11)	0.0034 (9)	0.0028 (9)	0.0014 (9)

Mo1—O5	1.737 (3)	Fe1—O8iv	1.961 (2)
Mo1—O6	1.768 (3)	Fe1—O3v	1.975 (2)
Mo1—O1i	1.775 (2)	Fe1—O2v	2.002 (2)
Mo1—O2ii	1.787 (2)	Fe1—O8vi	2.041 (2)
Mo2—O4	1.701 (3)	Fe1—O1v	2.101 (2)
Mo2—O7	1.707 (3)	Na1—O7vii	2.123 (4)
Mo2—O8	1.880 (2)	Na1—O5v	2.211 (3)
Mo2—O3	1.884 (2)	Na1—O4	2.252 (4)
Mo2—O3iii	2.400 (3)	Na1—O1v	2.286 (3)
Mo2—O5	2.636 (3)	Na1—O3v	2.306 (3)
Fe1—O6	1.947 (3)	Na1—O7vi	2.718 (4)
O5—Mo1—O6	107.29 (13)	O6—Fe1—O8iv	101.81 (11)
O5—Mo1—O1i	110.16 (12)	O6—Fe1—O3v	99.65 (12)
O6—Mo1—O1i	106.37 (12)	O8iv—Fe1—O3v	156.83 (11)
O5—Mo1—O2ii	110.72 (12)	O6—Fe1—O2v	88.11 (11)
O6—Mo1—O2ii	108.81 (12)	O8iv—Fe1—O2v	92.41 (10)
O1i—Mo1—O2ii	113.22 (11)	O3v—Fe1—O2v	96.92 (11)
O4—Mo2—O7	105.39 (15)	O6—Fe1—O8vi	174.67 (11)
O4—Mo2—O8	103.81 (12)	O8iv—Fe1—O8vi	78.88 (11)
O7—Mo2—O8	103.08 (13)	O3v—Fe1—O8vi	78.95 (10)
O4—Mo2—O3	103.37 (13)	O2v—Fe1—O8vi	97.16 (10)
O7—Mo2—O3	103.71 (13)	O6—Fe1—O1v	87.72 (11)
O8—Mo2—O3	134.72 (11)	O8iv—Fe1—O1v	84.61 (10)
O4—Mo2—O3iii	168.20 (13)	O3v—Fe1—O1v	87.65 (10)
O7—Mo2—O3iii	86.38 (13)	O2v—Fe1—O1v	174.27 (10)
O8—Mo2—O3iii	72.08 (9)	O8vi—Fe1—O1v	87.08 (10)
O3—Mo2—O3iii	73.94 (11)

Table 1

Selected bond lengths (Å)

Mo1—O5	1.737 (3)
Mo1—O6	1.768 (3)
Mo1—O1i	1.775 (2)
Mo1—O2ii	1.787 (2)
Mo2—O4	1.701 (3)
Mo2—O7	1.707 (3)
Mo2—O8	1.880 (2)
Mo2—O3	1.884 (2)
Mo2—O3iii	2.400 (3)
Mo2—O5	2.636 (3)
Fe1—O6	1.947 (3)
Fe1—O8iv	1.961 (2)
Fe1—O3v	1.975 (2)
Fe1—O2v	2.002 (2)
Fe1—O8vi	2.041 (2)
Fe1—O1v	2.101 (2)
Na1—O7vii	2.123 (4)
Na1—O5v	2.211 (3)
Na1—O4	2.252 (4)
Na1—O1v	2.286 (3)
Na1—O3v	2.306 (3)
Na1—O7vi	2.718 (4)

Symmetry codes: (i) ; (ii) ; (iii) ; (iv) ; (v) ; (vi) ; (vii) .