PHASE-RELATIONS IN THE SYSTEM LIGA-SN AND THE CRYSTAL-STRUCTURES OF THE INTERMEDIATE COMPOUNDS LIGASN AND LI2GA2SN

The quasibinary system LiGa-Sn contains the intermediate ternary phase s Li7Ga7Sn3, Li2Ga2Sn, Li5Ga5Sn3, Li3Ga3Sn2 and LiGaSn. Single crystal s of LiGaSn (a = 632.9(4) pm, Fd3m, Z = 4), Li3Ga3Sn2 (a = 445.4(3), c = 1 090.0(2) pm, hP), Li5Ga5Sn3 (a = 447.0(4), c = 4 220.0(9) pm, hP ) and Li2Ga2Sn (a = 441.1(2), c = 2164.5(7) pm, P6(3)/mmc, Z = 4) hav e been grown from the melt. The crystal structures of LiGaSn and Li2Ga 2Sn have been determined by single crystal X-ray methods (R = 0.029 bz w. 0.107 respectively). The crystal structure of LiGaSn contains a sph alerite-type Ga/Sn-arrangement, the Ga/Sn-arrangement of Li2Ga2Sn corr esponds to a stacking variant of the wurtzite- and sphalerite-type. Th e compounds can be classified in terms of the Zintl concept.