ThSi₂ type ytterbium disilicide and its analogues YbT_xSi_2-x (T = Cr, Fe, Co)

YbSi₂ and the derivatives YbT_xSi_2-x (T = Cr, Fe, Co) crystallizing in the α-ThSi₂ structure type were obtained as single crystals from reactions run in liquid indium. All silicides were investigated by single-crystal X-ray diffraction, I4₁/amd space group and the lattice constants are: a = 3.9868(6) Aa and c = 13.541(3) Aa for YbSi₂, a = 4.0123(6) Aa and c = 13.542(3) Aa for YbCr_0.27Si_1.73, a = 4.0142(6) Aa and c = 13.830(3) Aa for YbCr_0.71Si_1.29, a = 4.0080(6) Aa and c = 13.751(3) Aa for YbFe_0.34Si_1.66, and a = 4.0036(6) Aa, c = 13.707(3) Aa for YbCo_0.21Si_1.79. YbSi₂ and YbT_xSi_2-x compounds are polar intermetallics with three-dimensional Si and M (T+Si) polyanion sub-networks, respectively, filled with ytterbium atoms. The degree of substitution of transition metal at the silicon site is signficant and leads to changes in the average bond lengths and bond angles substantially. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)