Crystal structures of ternary compounds Yb(Ga,Si)2-x

The existence of two ternary compounds with AlB2and α-ThSi2-type structures was confirmed in the system Yb–Ga–Si at 600 and 500°C and their crystal structu res were refined by the Rietveld method for different compositions. In addition, a new ternary phase was found at 500°C: YbGa0.60(7)Si1.27(7) (structure type GdSi1.4, Pearson symbol oI12, space group Imma, a = 4.0646(5), b = 4.0634(4), c = 14.0796(9) Å). The structure types AlB 2, α-ThSi2, and GdSi1.4 are members of the family of structures with trigonal-prismatic coordination of the smaller atoms. Substitution of Si atoms for Ga atoms in the ternary phases leads to increased dimensionality of the network formed by the p-element atoms.