مطالعات پرتو ايكس M2GA6TE01

X-ray Studies on M2Ga6Te10

The phases M2Ga6Te10 (M: Li, Na) are obtained as black, homogeneous, microcrystalline samples and single crystals by direct reaction of the elements. According to the single crystal structure determinations both compounds crystallize in space group R32 (No. 155, Z=2) with the lattice constants: a=1436.9(2), c=1759.0(4) pm, Rw (all refl.)= 0.041, Rint=0.032, dx-Ray, (gcm^3)= 5.411 (T=290 K, Li2Ga6Te10). Their structure are characterized by tetrahedral close packings of Te^2-, corresponding to the arrangement of Mn atoms in Beta-Mn. While Ga^3+ ions are distributed in an ordered way over 12% of the tetrahedral holes, the Mʹ ions occupy all distrurted octahedral (`metaprismaticʹ) holes. As the Li+ ions are too small they occupy of center positions inside the, metaprisms. Positions with the strongest off-centering can only be refined on the basis of a split model. The results in this paper corresponds with the published by L. Kienle, H. J. Deiseroth and M. Hartung [2].