PMCCPMCCPMCC

Search tips
Search criteria 

Advanced

 
Logo of actaeInternational Union of Crystallographysearchopen accessarticle submissionjournal home pagethis article
 
Acta Crystallogr Sect E Struct Rep Online. 2010 May 1; 66(Pt 5): i39.
Published online 2010 April 17. doi:  10.1107/S1600536810013358
PMCID: PMC2979256

Disordered LiZnVO4 with a phenacite structure

Abstract

Single crystals of lithium zinc vanadate, LiZnVO4, were grown by the flux method. The structural type of this vanadate is characterized by a three-dimensional arrangement of tetra­hedra sharing apices in an LiZnVO4 network. This arrangement contains three different tetra­hedra, namely one [VO4] and two disordered mixed-site [Li/ZnO4] tetra­hedra. The resulting lattice gives rise to hexa­gonal channels running along the [0001] direction. Both sites in the mixed-site [Li/ZnO4] tetra­hedra are occupied by a statistical mixture of lithium and zinc with a 1:1 ratio. Therefore, LiZnVO4 appears to be the first vanadate known to crystallize with a disordered phenacite structure. Moreover, the resulting values of calculated bond valences (Li = 1.083, Zn = 2.062 and V = 5.185) tend to confirm the structural model.

Related literature

For related structural studies, see: Hartmann (1989 [triangle]); Capsoni et al. (2006 [triangle]); Zachariasen (1971 [triangle]). For compounds with the same structural type, see: Bu et al. (1996 [triangle]); Elammari & Elouadi (1989 [triangle]); Elouadi & Elammari (1990 [triangle]); Jensen et al. (1998 [triangle]). For bond-valence calculations, see: Brown & Altermatt (1985 [triangle]).

Experimental

Crystal data

  • LiZnVO4
  • M r = 187.25
  • Trigonal, An external file that holds a picture, illustration, etc.
Object name is e-66-00i39-efi1.jpg
  • a = 14.107 (3) Å
  • c = 9.441 (2) Å
  • V = 1627.1 (6) Å3
  • Z = 18
  • Mo Kα radiation
  • μ = 9.06 mm−1
  • T = 298 K
  • 0.14 × 0.12 × 0.10 mm

Data collection

  • Bruker X8 APEXII CCD area-detector diffractometer
  • Absorption correction: multi-scan (SADABS; Sheldrick, 2003 [triangle]) T min = 0.292, T max = 0.404
  • 9709 measured reflections
  • 1622 independent reflections
  • 1213 reflections with I > 2σ(I)
  • R int = 0.070

Refinement

  • R[F 2 > 2σ(F 2)] = 0.024
  • wR(F 2) = 0.055
  • S = 1.04
  • 1622 reflections
  • 69 parameters
  • Δρmax = 0.51 e Å−3
  • Δρmin = −0.53 e Å−3

Data collection: APEX2 (Bruker, 2005 [triangle]); cell refinement: SAINT (Bruker, 2005 [triangle]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 [triangle]) and PLATON (Spek, 2009 [triangle]); software used to prepare material for publication: WinGX (Farrugia, 1999 [triangle]).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810013358/fj2291sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810013358/fj2291Isup2.hkl

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

Acknowledgments

The authors thanks the Unit of Support for Technical and Scientific Research (UATRS, CNRST) for the X-ray measurements.

supplementary crystallographic information

Comment

Our particular interest here is to investigate the form nature of the crystallized phase and determine the structural type that could result from the association of small size cations likely to enter under normal conditions of pressure and temperature, tetrahedral cavities of oxides like in phenacite Be2SiO4 network (Hartmann, 1989; Zachariasen, 1971). The compounds currently known to crystallize with such structural type are LiZnPO4 (Bu et al., 1996; Elammari & Elouadi, 1989; Elouadi & Elammari, 1990) and LiZnAsO4 (Jensen et al., 1998).

The structural type of the title compound, related to the phenacite structure, could be described (Fig.1) as three dimensional arrangement of [MO4] tetrahedra ( M= Li/Zn or V) sharing apices. The arrangement concerns three different types of tetrahedra [VO4] and two disordered sites [Li/ZnO4] which give rise to an overall disordered phenacite structure. When viewed along the c axis, the packing of [MO4] tetraherdra results in two types of tunnels: large hexagonal tunnels surrounded by six lozenge like channels (rings of four tetrahedra). Similar description has recently been reported by Capsoni et al. (2006) using a powder x-ray diffraction data of LiZnVO4. However, a careful observation of the two models can highlights the difference between our two results. Indeed, in addition to the difference of the lengths of chemical bonds, the occupancy rate of cationic Wycoff sites is different. Thus, in our model, there is only a disorder between Li and Zn with a statistical distribution of both ions on the two crystallographic sites, while the third site is only occupied by vanadium cation. Furthermore, A bond-valence analysis (Li <1.083>, Zn<2.062> and <V<5.185>) based on the empirical formula proposed by Brown & Altermatt (1985) is in favor of this model . The cationic disorder mentioned by Capsoni et al. could be seen as due to preparation methods. The powder used was slowly cooled from 853 K after 24 h sintering. Whereas, the growth of our crystal, from a flux melted at 1073 k and slowly cooled with a rate of 5 K h-1. Thus the resulting sintering of our crystal was much longer. A more ordred system is then to be expected.

When such structural type is seen as a close packing of oxygen anions, it appears as a lacunar hexagonal close packing of O2- ions. Fig.2 shows a typical oxygen layer and the elevation of such oxygen plans as successively stacked ( ABAB···) along [0001]. The coordination sphere of all cations is of tetrahedral type. The analysis of oxygen environment shows a regular triangular cavity for O2- anions with an average edge length of <V—Li/Zn> = 3.240 Å.

In the case of the present form of LiZnVO4, the disordered phenacite structure was attributed to the existence of a mixed tetrahedral site [Li/ZnO4] occupied by both Li and Zn. The resulting space group is R-3. LiZnVO4 is probably the first vanadate known to crystallize with a disordered phenacite structure.

Experimental

Prior to the crystal growth, pulverulent samples of the compound LiZnVO4 and the flux LiVO3 are synthesized by the regular solid state reaction according to the following reactions:

Li2CO3 + 2ZnO + V2O5 —> 2LiZnVO4 + CO2 Li2CO3 + V2O5 —> 2LiVO3 + CO2

Single crystal of the monovanadate LiZnVO4 were grown from a bath of equimolar mixture of freohly prepared powders of LiZnVO4 and LiVO3. The starting mixture was thoroughly ground before to be melted at 1073 K in a platinum crucible and slowly cooled with a rate of 5 K h-1 to 773 K. The furnace was then switched off and the whole system naturally cooled down to room temperature. Single crystal s were collected from the crucible after dissolwing the flux in warmed water.

Figures

Fig. 1.
: A three-dimensional view of LiZnVO4 crystal structure, showing tunnels runnig along the c axis.
Fig. 2.
: Partial projection of the crystal structure on (0 0 1), showing lacunar hexagonal close packing of O2- ions.

Crystal data

LiZnVO4Dx = 3.440 Mg m3
Mr = 187.25Mo Kα radiation, λ = 0.71073 Å
Trigonal, R3Cell parameters from 9709 reflections
Hall symbol: -R 3θ = 10–30°
a = 14.107 (3) ŵ = 9.06 mm1
c = 9.441 (2) ÅT = 298 K
V = 1627.1 (6) Å3Prism, pale yellow
Z = 180.14 × 0.12 × 0.10 mm
F(000) = 1584

Data collection

Bruker X8 APEXII CCD area-detector diffractometer1622 independent reflections
Radiation source: fine-focus sealed tube1213 reflections with I > 2σ(I)
graphiteRint = 0.070
[var phi] and ω scansθmax = 35.2°, θmin = 4.0°
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)h = −22→22
Tmin = 0.292, Tmax = 0.404k = −22→22
9709 measured reflectionsl = −15→15

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.024w = 1/[σ2(Fo2) + (0.0124P)2 + 2.5069P] where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.055(Δ/σ)max = 0.001
S = 1.04Δρmax = 0.51 e Å3
1622 reflectionsΔρmin = −0.53 e Å3
69 parametersExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
0 restraintsExtinction coefficient: 0.0088 (2)

Special details

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 on F2 for ALL reflections except for 0 with very negative F2 or flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The observed criterion of F2 > σ(F2) is used only for calculating -R-factor-obs 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 (Å2)

xyzUiso*/UeqOcc. (<1)
V10.454581 (17)0.138171 (16)0.08352 (2)0.00790 (7)
Zn10.45273 (2)0.14015 (2)−0.24915 (3)0.01132 (7)0.50
Li10.45273 (2)0.14015 (2)−0.24915 (3)0.01132 (7)0.50
Zn20.64622 (2)0.12175 (3)0.24882 (3)0.01150 (7)0.50
Li20.64622 (2)0.12175 (3)0.24882 (3)0.01150 (7)0.50
O10.34102 (7)0.01142 (7)0.08427 (11)0.01335 (17)
O20.56475 (8)0.11882 (9)0.08215 (10)0.01353 (17)
O30.45578 (8)0.20780 (8)−0.06565 (10)0.01419 (18)
O40.45936 (8)0.20728 (8)0.23409 (10)0.01377 (17)

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
V10.00918 (10)0.00812 (10)0.00692 (9)0.00472 (8)−0.00012 (6)−0.00004 (6)
Zn10.01190 (12)0.01217 (13)0.01038 (12)0.00637 (10)0.00052 (9)0.00069 (9)
Li10.01190 (12)0.01217 (13)0.01038 (12)0.00637 (10)0.00052 (9)0.00069 (9)
Zn20.01159 (13)0.01368 (13)0.01016 (12)0.00701 (10)0.00005 (9)0.00037 (9)
Li20.01159 (13)0.01368 (13)0.01016 (12)0.00701 (10)0.00005 (9)0.00037 (9)
O10.0109 (4)0.0102 (4)0.0180 (4)0.0046 (3)−0.0010 (3)0.0000 (3)
O20.0121 (4)0.0198 (4)0.0115 (3)0.0101 (3)−0.0005 (3)−0.0005 (3)
O30.0219 (5)0.0120 (4)0.0103 (3)0.0096 (3)−0.0007 (3)0.0009 (3)
O40.0209 (4)0.0125 (4)0.0104 (4)0.0102 (4)0.0003 (3)−0.0004 (3)

Geometric parameters (Å, °)

V1—O11.7027 (10)Zn2—O21.9368 (10)
V1—O41.7059 (10)Zn2—O4x1.9495 (10)
V1—O21.7071 (10)Zn2—O4xi1.9676 (11)
V1—O31.7123 (10)Zn2—Li1iv3.1441 (8)
V1—Li2i3.1568 (7)Zn2—Zn1iv3.1441 (8)
V1—Li1ii3.1719 (8)Zn2—Li1viii3.2314 (8)
V1—Li2iii3.2409 (8)Zn2—Li2i3.2675 (7)
V1—Li1iv3.2523 (6)Zn2—Li2x3.2676 (7)
V1—Li2v3.2978 (7)O1—Li2iii1.9294 (11)
V1—Li1vi3.3232 (7)O1—Zn2iii1.9294 (11)
Zn1—O2vi1.9410 (10)O1—Zn1ii1.9442 (11)
Zn1—O1vii1.9441 (11)O1—Li1ii1.9442 (11)
Zn1—O3iv1.9588 (11)O2—Li1iv1.9411 (10)
Zn1—O31.9679 (11)O2—Zn1iv1.9411 (10)
Zn1—Zn2vi3.1441 (8)O3—Li1vi1.9587 (11)
Zn1—Li2vi3.1441 (8)O3—Zn1vi1.9587 (11)
Zn1—Li2viii3.2314 (8)O4—Li2i1.9496 (10)
Zn1—Li1vi3.2765 (7)O4—Zn2i1.9496 (10)
Zn1—Li1iv3.2766 (7)O4—Li2v1.9676 (11)
Zn2—O1ix1.9294 (11)O4—Zn2v1.9676 (11)
O1—V1—O4110.14 (5)O2vi—Zn1—O3115.71 (4)
O1—V1—O2106.61 (5)O1vii—Zn1—O3106.57 (4)
O4—V1—O2108.58 (5)O3iv—Zn1—O3110.08 (5)
O1—V1—O3109.88 (5)O1ix—Zn2—O2111.98 (5)
O4—V1—O3111.80 (5)O1ix—Zn2—O4x108.76 (4)
O2—V1—O3109.69 (5)O2—Zn2—O4x117.26 (4)
O2vi—Zn1—O1vii109.39 (5)O1ix—Zn2—O4xi102.55 (4)
O2vi—Zn1—O3iv106.12 (4)O2—Zn2—O4xi107.30 (4)
O1vii—Zn1—O3iv108.84 (4)O4x—Zn2—O4xi107.87 (5)

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

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: FJ2291).

References

  • Brown, I. D. & Altermatt, D. (1985). Acta Cryst. B41, 244–247.
  • Bruker (2005). APEX2 and SAINT Bruker AXS Inc., Madison, Wisconsin, USA.
  • Bu, X., Gier, T. E. & Stucky, G. D. (1996). Acta Cryst. C52, 1601–1603.
  • Capsoni, D., Bini, M., Massarotti, V., Mustarelli, P., Belotti, F. & Galinetto, P. (2006). J. Phys. Chem. B, 110, 5409–5415. [PubMed]
  • Elammari, L. & Elouadi, B. (1989). Acta Cryst. C45, 1864–1867.
  • Elouadi, B. & Elammari, L. (1990). Ferroelectrics, 107, 253–258.
  • Farrugia, L. J. (1997). J. Appl. Cryst.30, 565.
  • Farrugia, L. J. (1999). J. Appl. Cryst.32, 837–838.
  • Hartmann, P. (1989). Z. Kristallogr.187, 139–143.
  • Jensen, T. R., Norby, P., Hanson, J. C., Simonsen, O., Skou, E. M., Stein, P. C. & Boye, H. A. (1998). J. Mater. Chem.8, 969–975.
  • Sheldrick, G. M. (2003). SADABS University of Göttingen, Germany.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Spek, A. L. (2009). Acta Cryst. D65, 148–155. [PMC free article] [PubMed]
  • Zachariasen, W. H. (1971). Kristallografiya, 16, 1161–1166.

Articles from Acta Crystallographica Section E: Structure Reports Online are provided here courtesy of International Union of Crystallography