LiCo2As3O10: une nouvelle structure à tunnels inter-connectés.

The title compound, lithium dicobalt(II) triarsenate, LiCo2As3O10, was synthesized by a solid-state reaction. The As atoms and four out of seven O atoms lie on special positions, all with site symmetry m. The Li atoms are disordered over two independent special (site symmetry -1) and general positions with occupancies of 0.54 (7) and 0.23 (4), respectively. The structure model is supported by bond-valence-sum (BVS) and charge-distribution (CHARDI) methods. The structure can be described as a three-dimensional framework constructed from bi-octahedral Co2O10 dimers edge-connected to As3O10 groups. It delimits two sets of tunnels, running parallel to the a and b axes, the latter being the larger. The Li(+) ions are located within the inter-sections of the tunnels. The possible motion of the alkali cations has been investigated by means of the BVS model. This simulation shows that the Li(+) motion appears to be easier mainly along the b-axis direction and that this material may possess inter-esting conduction properties.

Related literature

The investigated compound is the only arsenic member of the isotypic analogues LiM 2 X 3O10 (M = Fe, Co, Ni; X = P, As; Erragh et al., 1996 ▶; Ramana et al., 2006 ▶). For bond-valence-sum analysis, see: Brown (2002 ▶); Adams (2003 ▶). For the charge-distribution method, see: Nespolo (2001 ▶); Nespolo et al. (2001 ▶); Guesmi et al. (2006 ▶). For BVS pathway simulation, see: Mazza (2001 ▶); Ouerfelli et al. (2007 ▶). For a related compound, see: Satya Kishore & Varadaraju (2006 ▶).

Experimental

Crystal data

LiCo2As3O10

M = 509.56

Monoclinic,

a = 4.830 (2) Å

b = 8.721 (2) Å

c = 9.3269 (9) Å

β = 98.08 (3)°

V = 388.97 (19) Å3

Z = 2

Mo Kα radiation

μ = 16.97 mm−1

T = 298 K

0.14 × 0.10 × 0.07 mm

Data collection

Enraf–Nonius CAD-4 diffractometer

Absorption correction: ψ scan (North et al., 1968 ▶) T min = 0.200, T max = 0.383

2027 measured reflections

903 independent reflections

816 reflections with I > 2σ(I)

R int = 0.024

2 standard reflections every 120 reflections intensity decay: 3%

Refinement

R[F 2 > 2σ(F 2)] = 0.023

wR(F 2) = 0.063

S = 1.10

903 reflections

82 parameters

1 restraint

Δρmax = 1.13 e Å−3

Δρmin = −0.90 e Å−3

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1995 ▶); 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, 2001 ▶); software used to prepare material for publication: WinGX (Farrugia, 2012 ▶) and publCIF (Westrip, 2010 ▶).

Click here for additional data file.

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536813013548/br2224sup1.cif

Click here for additional data file.

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536813013548/br2224Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

LiCo2(As3O10)	F(000) = 472
Mr = 509.56	Dx = 4.351 Mg m−3
Monoclinic, P21/m	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yb	Cell parameters from 25 reflections
a = 4.830 (2) Å	θ = 12.4–14.8°
b = 8.721 (2) Å	µ = 16.97 mm−1
c = 9.3269 (9) Å	T = 298 K
β = 98.08 (3)°	Parallelepiped, pink
V = 388.97 (19) Å3	0.14 × 0.10 × 0.07 mm
Z = 2

Enraf–Nonius CAD-4 diffractometer	816 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.024
Graphite monochromator	θmax = 27.0°, θmin = 2.2°
ω/2θ scans	h = −6→6
Absorption correction: ψ scan (North et al., 1968)	k = −1→11
Tmin = 0.200, Tmax = 0.383	l = −11→11
2027 measured reflections	2 standard reflections every 120 reflections
903 independent reflections	intensity decay: 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)] = 0.023	w = 1/[σ2(Fo2) + (0.0372P)2 + 0.4094P] where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.063	(Δ/σ)max = 0.007
S = 1.10	Δρmax = 1.13 e Å−3
903 reflections	Δρmin = −0.90 e Å−3
82 parameters	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
1 restraint	Extinction coefficient: 0.0240 (13)

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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)
Co1	1.03666 (8)	0.93447 (6)	0.83555 (4)	0.00531 (17)
As1	0.45631 (9)	0.7500	0.65408 (5)	0.00377 (16)
As2	0.61125 (9)	0.7500	0.02638 (5)	0.00327 (16)
As3	0.33999 (10)	0.7500	0.32284 (5)	0.00419 (16)
O1	0.5921 (7)	0.7500	0.2116 (4)	0.0104 (5)
O2	0.5743 (7)	0.7500	0.4830 (4)	0.0104 (5)
O3	1.2865 (7)	0.7500	0.9368 (4)	0.0070 (7)
O4	0.7674 (7)	0.7500	0.7587 (4)	0.0070 (7)
O5	0.8393 (5)	1.0887 (3)	0.6836 (3)	0.0116 (5)
O6	0.7861 (5)	0.9132 (3)	1.0088 (3)	0.0071 (5)
O7	1.2675 (5)	0.9089 (3)	0.6622 (3)	0.0086 (5)
Li1A	1.0000	1.0000	0.5000	0.007 (3)*	0.54 (7)
Li1B	0.947 (8)	0.973 (4)	0.500 (3)	0.007 (3)*	0.23 (4)

	U11	U22	U33	U12	U13	U23
Co1	0.0062 (3)	0.0054 (3)	0.0042 (3)	−0.00006 (14)	0.00014 (19)	−0.00079 (15)
As1	0.0035 (2)	0.0057 (3)	0.0019 (3)	0.000	−0.00053 (18)	0.000
As2	0.0028 (2)	0.0041 (3)	0.0026 (3)	0.000	−0.00044 (18)	0.000
As3	0.0043 (2)	0.0056 (3)	0.0024 (3)	0.000	−0.00020 (17)	0.000
O1	0.0079 (10)	0.0216 (13)	0.0021 (11)	0.000	0.0021 (9)	0.000
O2	0.0079 (10)	0.0216 (13)	0.0021 (11)	0.000	0.0021 (9)	0.000
O3	0.0048 (15)	0.0064 (15)	0.0083 (17)	0.000	−0.0039 (13)	0.000
O4	0.0074 (15)	0.0079 (15)	0.0045 (15)	0.000	−0.0029 (13)	0.000
O5	0.0129 (12)	0.0103 (11)	0.0111 (12)	0.0059 (10)	−0.0006 (10)	0.0012 (10)
O6	0.0071 (11)	0.0070 (10)	0.0076 (12)	−0.0045 (10)	0.0021 (9)	−0.0032 (10)
O7	0.0104 (11)	0.0088 (11)	0.0076 (11)	0.0050 (10)	0.0047 (9)	0.0020 (10)

Co1—O6i	2.063 (3)	As3—O5viii	1.649 (3)
Co1—O5	2.085 (3)	As3—O1	1.707 (3)
Co1—O7	2.100 (3)	As3—O2	1.743 (4)
Co1—O4	2.129 (2)	Li1A—Li1B	0.35 (5)
Co1—O3	2.148 (2)	Li1A—O7	2.010 (2)
Co1—O6	2.159 (2)	Li1A—O7ix	2.010 (2)
As1—O7ii	1.667 (2)	Li1A—O5	2.123 (3)
As1—O7iii	1.667 (2)	Li1A—O5ix	2.123 (3)
As1—O4	1.673 (3)	Li1B—Li1Bix	0.70 (10)
As1—O2	1.768 (3)	Li1B—O7ix	1.99 (3)
As2—O3iv	1.670 (3)	Li1B—O7	2.08 (3)
As2—O6v	1.675 (2)	Li1B—O5	2.11 (3)
As2—O6vi	1.675 (2)	Li1B—O5ix	2.19 (3)
As2—O1	1.743 (3)	Li1B—O2	2.64 (3)
As3—O5vii	1.649 (3)
O6i—Co1—O5	99.67 (12)	O7iii—As1—O4	115.20 (10)
O6i—Co1—O7	113.41 (10)	O7ii—As1—O2	106.80 (10)
O5—Co1—O7	77.67 (10)	O7iii—As1—O2	106.80 (10)
O6i—Co1—O4	153.78 (12)	O4—As1—O2	98.59 (16)
O5—Co1—O4	93.40 (11)	O3iv—As2—O6v	113.71 (10)
O7—Co1—O4	91.49 (12)	O3iv—As2—O6vi	113.71 (10)
O6i—Co1—O3	91.20 (10)	O6v—As2—O6vi	116.39 (17)
O5—Co1—O3	163.09 (12)	O3iv—As2—O1	108.59 (17)
O7—Co1—O3	86.15 (12)	O6v—As2—O1	101.23 (10)
O4—Co1—O3	82.01 (11)	O6vi—As2—O1	101.23 (10)
O6i—Co1—O6	75.48 (10)	O5vii—As3—O5viii	117.15 (18)
O5—Co1—O6	108.27 (10)	O5vii—As3—O1	113.20 (10)
O7—Co1—O6	168.82 (11)	O5viii—As3—O1	113.20 (10)
O4—Co1—O6	78.87 (11)	O5vii—As3—O2	107.79 (11)
O3—Co1—O6	86.90 (12)	O5viii—As3—O2	107.79 (11)
O7ii—As1—O7iii	112.51 (17)	O1—As3—O2	95.06 (17)
O7ii—As1—O4	115.20 (10)

Cation	q(i).sof(i)	Q(i)	V(i)	CN(i)	ECoN(i)	dmoy	dmed
As1	5,00	5,043	4,987	4	3,915	1,693	1,687
As2	5,00	4,967	5,039	4	3,958	1,690	1,687
As3	5,00	4,958	5,007	4	3,921	1,686	1,681
Co1	2,00	2,015	2,014	6	5,944	2,114	2,110
Li1A	0,54	0,540	0,464	4	3,894	2,067	2,056
Li1B	0,23	0,230	0,194	5	3,951	2,205	2,085