Ab initio Structure Determination of New Boride CePt3B, a Distorted Variant of CaTiO3.

Abstract The crystal structure of the new ternary boride CePt 3 B, tetragonal, space group P4mm (N99), a =4.00433(18) A, c =5.07547(7) A, Z =1, V =81.383(5) A 3 was determined ab initio from X-ray powder diffraction using conventional and synchrotron radiation, optical metallographic examination and electron probe micro-analysis (EPMA). Rietveld refinement on the sample with composition Ce 20 Pd 60 B 20 revealed the presence of two phases, 95% of cubic CePd 3 B x , x =0.6 (space group Pm-3m , CaTiO 3 str. type, a =4.19350(11) A) and 5% of CeB 6 (space group Pm-3m , CaB 6 str. type, a =4.1389(2) A). Magnetic susceptibility measurements and X-ray absorption spectroscopy show that Ce is in a trivalent state in CePt 3 B and that the compound does not order magnetically at 2 K.