RMX compounds formed by alkaline earths, europium and ytterbium IV: Ternary phases with M = Ag and X = Si, Ge, Sn, Pb

The ternary RAgX phases, with R = Ca, Sr, Ba, Eu, Yb and X = Si, Ge, Sn, Pb, were structurally studied by means of X-ray diffraction on powders and single crystals. The tin and lead compounds exist on the equiatomic composition and crystallize in the CeCu2, CaLiSn and YbAgPb types. The silicon and germanium compounds are in most cases nonstoichiometric and belong to the CeCu2 and AlB2 types, and to three new variants of the AlB2 structure: SrAgGe, Ba3Ag2Si3, Ca5Ag2Si7. The influence of the electron concentration factor on the stability of the different atomic arrangements is pointed out.