The crystal structures of LaRu4P12 and CeRu4P12 are refined by the Rietveld
analysis of the powder X-ray diffraction data. The bond distances and bond
angles in both phosphides are obtained. La1-xCexRu4P12(x = 0, 0.1, 0.2, 0.
3, 0.4, 0.5, 0.6, 0.7, 0.75, 0.8, 0.9, and 1) and CeOs4P12 are prepared at
high temperatures and high pressures. Powder X-ray diffractions of the allo
ys are studied at room temperature. The lattice parameters of the alloys do
not change linearly with increasing x and markedly deviate from linear bet
ween x<0.4 and x = 0.6. The formal oxidation number of Ce atoms in the allo
ys is +3 below x = 0.6. The electrical and magnetic properties of the alloy
s CeRu4P12 and CeOs4P12 are studied at low temperatures. The metal-to-insul
ator transition and magnetic ordering appear at around x = 0.6. Above x = 0
.7 the alloys behave as a semiconductor. CeOs4P12 exhibits a semiconducting
behavior,with an activation energy of 0.034 eV. CeRu4P12 and CeOs4P12 show
a very small, nearly temperature-independent susceptibility. Electrical an
d magnetic properties of the alloys, CeRu4P12 and CeOs4P12 are discussed. (
C) 1999 Academic Press.