Identification and structural characterization of Ca(PtxCu(1-x))(3)O-4

We describe a new compound, Ca(PtxCu(1-x))(3)O-4 (0.2 < x < 0.3), which is only the second- known quaternary compound of an alkaline earth metal with platinum, copper, and oxygen. The composition and structure were determined with an electron probe using wave-dispersive spectrometry (WDS), electron diffraction, and powder X-ray diffraction. The present material crystallize s in the Pt bronze structure, a cubic cell with a = 5.6270(2) Angstrom, and space group Pm (3) over bar n (no. 223). The Cu and Pt atoms are randomly distributed onto the same position, comprising nonintersecting chains in ea ch of the three coordinate directions. The material is an n-type semiconduc tor. (C) 2000 Elsevier Science Ltd.