Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S160053680100201X/br6002sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S160053680100201X/br6002Isup2.hkl |
Key indicators
- Single-crystal X-ray study
- T = 293 K
- R factor = 0.022
- wR factor = 0.055
- Data-to-parameter ratio = 16.0
checkCIF results
No syntax errors found
ADDSYM reports no extra symmetry
Alert Level A:
GEOM_005 Alert A _geom_angle_atom_site_label_1 is missing Label identifying the atom site 1. GEOM_006 Alert A _geom_angle_atom_site_label_2 is missing Label identifying the atom site 2. GEOM_007 Alert A _geom_angle_atom_site_label_3 is missing Label identifying the atom site 3. GEOM_008 Alert A _geom_angle is missing Angle between atom sites 1, 2 and 3.
Alert Level C:
ABSTY_02 Alert C An _exptl_absorpt_correction_type has been given without a literature citation. This should be contained in the _exptl_absorpt_process_details field. Absorption correction given as numerical CRYSR_01 Alert C _exptl_crystal_size_rad not in the CIF when expected. General Notes
ABSTM_02 The ratio of expected to reported Tmax/Tmin(RR) is > 1.10 Tmin and Tmax reported: 0.439 0.541 Tmin and Tmax expected: 0.310 0.458 RR = 1.200 Please check that your absorption correction is appropriate.
4 Alert Level A = Potentially serious problem
0 Alert Level B = Potential problem
2 Alert Level C = Please check
In the aim of obtaining the ternary compound Li4Ba3Sb4, amounts of Li, Ba and Sb (in proportion 4/3/4) were inserted in a niobium reactor, then weld-sealed under argon·The niobium reactor was protected against oxidation inside an evacuated silica tube. Single crystals of LiBaSb were obtained as side products by heating the initial mixture at 780 K for 10 h, maintaining at 580 K for 3 days and quenching in air. Elemental analyses (SEM) of crystals confirmed the presence of barium and antimony nearly in the ratio 1:1. The air-sensitive crystals were inserted into Lindemann glass capillaries for X-ray data investigations. Parameters and crystallographic space group were initially determined by oscillation and Weissenberg techniques. The best diffracting crystal was used for accurate intensity measurements on a CAD-4 Nonius diffractometer. Space group was found to be P63/mmc (n° 194) (observation conditions: 00 (0) l for l = 2n and hh(-2 h)l for l=2n).
All computations were carried out on a Pentium II 266 computer. The structure representation has been drawn with the program ORTEP-3 for Windows (Farrugia, 1997) which is a MS-Windows version of the current release of ORTEP-III (Burnett & Johnson).
? | β = ?° |
Mr = ? | γ = ?° |
?, ? | V = ? Å3 |
a = ? Å | Z = ? |
b = ? Å | ? radiation, λ = ? Å |
c = ? Å | × × mm |
α = ?° |
Experimental details
Crystal data | |
Chemical formula | ? |
Mr | ? |
Crystal system, space group | ?, ? |
Temperature (K) | ? |
a, b, c (Å) | ?, ?, ? |
α, β, γ (°) | ?, ?, ? |
V (Å3) | ? |
Z | ? |
Radiation type | ?, λ = ? Å |
µ (mm−1) | ? |
Crystal size (mm) | × × |
Data collection | |
Diffractometer | ? |
Absorption correction | ? the absorption effects have been corrected using the numerical procedure provided by SHELX 76 program (Sheldrick, 1976) |
No. of measured, independent and observed (?) reflections | ?, ?, ? |
Rint | ? |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | ?, ?, ? |
No. of reflections | ? |
No. of parameters | ? |
No. of restraints | ? |
Δρmax, Δρmin (e Å−3) | ?, ? |
The structure of LiBaSb has been determined in the centrosymmetric space group P63/mmc (No. 194). Ba and Sb atoms were refined anisotropically, and an attempt to refine the Li atom anisotropically resulted in an uncertainties/Uij ratio that was too large. This compound is isostructural with KZnSb (Savelsberg & Schaefer, 1986) and NaBeSb (Tiburtius & Schuster, 1977), but the atomic positions of the monovalent and divalent cations are exchanged. In the LiBaSb structure, Li occupies the 6m2 site and Ba the 3 m site, while in KZnSb (or NaBeSb), K (or Na) sits at 3 m and Zn (or Be) at 6m2. The ionic radius of Li+ (0.90 Å) is closer to that of Zn2+ (0.88 Å) (or Be2+ 0.60 Å) than to that of K+ (1.52 Å) [or Na+ (1.20 Å)]. This favors exchange of monovalent/divalent atom positions. This structure can be considered as a filled NiAs-type structure or is better described as a substituted Li3Sb structure; one Ba2+ substitutes two Li+ cations. The LiBaSb structure adopts the same space group as Li3Sb. Owing to the largest size of the barium cations (Ba2+ 1.49 Å) compared with Li+ (0.9 Å), the cell parameters of the ternary phase are expanded (a = 4.701 Å and c = 8.309 Å in Li3Sb). Atomic positions are different from those in the binary phase. The structure of LiBaSb may be described with hexagonal prisms Ba(Li3Sb3)2 fused along the c axis. The barium cations are surrounded by 6 Li and 6 Sb atoms at 3.616 (1) Å. The Sb atoms are coordinated to three Li cations at 2.828 Å, close to the Li—Sb distance in Li3Sb (2.71 and 2.77 Å), and to six Ba cations at 3.616 (1) Å.
Unlike the parent Li4Ba3As4 compound (Monconduit & Belin, 1999), which contains two anionic moieties, namely As24- dumbbells and isolated As3- anions, and was characterized as a large band semi-conductor, the LiBaSb (Li+Ba2+Sb3-) compound contains only isolated Sb3- anions in association with Li+ and Ba2+ cations and is an insulator.