LiGaGe-type structure

The structure types Caln2, ZrBeSi, NdPtSb, LiGaGe, CaLiSn,... 

Number 1 corresponds to AIB2 structure type 2 - ZrBeSi 3 - MgAgAs 4 - Caln2 5 - TiNiSi 6 - LiGaGe 7-KHg2 8-CeScSi. 

Nd-Pt-Sb. NdPtSb crystallizes with the Caln2 type structure, a = 0.4544, c = 0.7878 (Rossi et al., 1981 powder X-ray diffraction data). For the experimental details, see the LaPtSb. At variance with these data, Wenski and Mewis (1986a) reported the LiGaGe type structure for the NdPtSb compound, a = 0.4535, c = 0.7866 from X-ray single crystal investigation. For the sample preparation, see PrPtSb. 

Yb-Au-Sb. The LiGaGe type was established for the YbAuSb compound (a = 0.4635, c = 0.7765) by Merlo et al. (1990) by means of powder and single crystal diffraction method on a sample obtained by melting stoichiometric amounts of the components in iron or in tantalum crucibles and arc welded shut under an argon atmosphere. After slow cooling, no further thermal treatments were applied. The purities of the metals were Yb 99.9%, Au and Sb 99.999%. The crystal structure was confirmed by Flandorfer et al. (1997) by X-ray powder diffraction. 

LaAgGe (3) with the LiGaGe-type of structure (a=0.45587, c=0.78969 X-ray powder diffraction data) was observed by Pecharsky et al. (1991) from arc melted alloy heat-treated at 1023K in a helium-filled sealed quartz tube for one week. The lanthanum was 99.79 mass% pure the silver was 99.99 mass% pure and the germanium was 99.999 mass% pme. 

Only one report exists on the interaction of components in the ternary Yb-Au-Ge system Rossi et al. (1992) observed and characterized the YbAuGe compound as having the LiGaGe-type structure with lattice parameters a=0.4475, c=0.7163 (X-ray powder diffraction). The sample was obtained by melting the metals in an induction fiimace and annealing at 1070 K for one week. The metals used had a purity of around 99.9mass.% for Yb and 99.99 mass.% for Au and Ge. 

Fig. 15. Structures of (a) low- (LiGaGe-type) and (b) high-temperature YbCuBi (ZrBeSi-type).

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