On the cerium valence in ternary compounds CeMSb(2) and CeM'Bi-2; M=Mn,Fe,Co,Ni,Cu,Zn,Pd,Ag,Au and M'=Ni,Cu,Zn,Ag

Ternary compounds CeMSb(2) and CeM'Bi-2 have been synthesized by are melting followed by a heat treatment at 400, 600 or 800 degrees C for 300 h. Bismuth-containing compounds have been observed for the first time. From X-ray powder diffractometry all compounds were found to be isotypic with ZrCuSi2-type. In CeMn0.9Sb2, the manganese sublattice orders ferromagnetically at T similar to 130 K, and the cerium sublattice shows additional ordering at similar to 20 K. CeMSb(2) (M=Fe, Ni, Pd, Cu, Ag, Au, Zn) are antiferromagnets below T=12 K. In the paramagnetic regime, the cerium atom adopts the Ce-F-2(5/2) tripositive groundstate. CeCu0.9Bi2 is also an antiferromagnet, whereas for Ce(Ag,Zn)Bi-2 no magnetic order was encountered. X-Ray absorption spectroscopy shows that Ce in all compounds CeMSb(2) and CeMBi(2) is in the trivalent, or nearly trivalent, state.