Synthesis and structure of Li_(4.82(2))Pd_(2.90(2))Si_(2.28(2))

摘要

The lithium-rich silicide Li_(4.82(2))Pd_(2.90(2))Si_(2. 28(2)) was obtained by melting of palladium and silicon in an excess of lithium using a sealed niobium ampoule as container material. The structure of this new silicide was refined on the basis of single crystal X-ray diffractometer data: P4_32_12, a = 679.1(1), c = 3774. 7(8) pm, wR2 = 0.0712, Flack 0.03(11), 2072 F~2 values, and 108 variables. The polar Li_(4.82(2))Pd_(2.90(2)_Si_(2.28( 2)) structure consists of a complex three-dimensional [ Pd_(2.90(2))Si_(2.28(2))] network which leaves larger channels along the c direction which are filled by the lithium atoms. One lithium site shows a mixed occupancy with silicon and two palladium sites show Pd/Si mixing, leading to the composition Li_(4.82(2))Pd_(2.90(2))Si_(2.28(2)) for the investigated crystal.