Crystal structure and physical properties of Yb-based intermetallics Yb(Cu, Ag)2(Si, Ge)2, Yb(Cu1−xZnx)2Si2 (x = 0.65, 0.77) and Yb(Ag0.18Si0.82)2

X-ray powder data for YbCu2Ge2, YbAg2Si2 and YbAg2Ge2 confirmed the atom order of the ThCr2Si2 type (ordered BaAl4 type) as reported earlier. YbCu2Ge2 is an intermediate valence system with the Yb ions valence close to +2 at low temperatures, whereas the other two compounds are weakly temperature-dependent paramagnets. All these ternaries show metallic character of their electrical conductivity. The structure of Yb(Cu1−xZnx)2Si2 (x = 0.65, 0.77) was found to correspond to the BaAl4 type, assuming a random distribution of Cu and Zn atoms over the positions 4d (0, 1/2, 1/4). The Si atoms were found in the sites 4e (0, 0, z). These two pseudoternary compounds are diamagnetic. A novel phase with the composition Yb(Ag0.18Si0.82)2 crystallizes in the ThSi2-type on the verge to a symmetry reduction towards orthorhombic GdSi2-type. This phase is a Pauli paramagnet and exhibits metallic behavior of the resistivity.