Crystal Structure and Magnetic Properties of Sm3ReO7

Crystals of a new ternary samarium rhenium oxide, Sm3ReO7were obtained by subsolidus reaction of samariumsesquioxide and rheniumdioxide (ratio 1.5:1) in sealed Pt–10Rh-tubes at 1673 K. The structure was determined by single-crystal X-ray diffraction. Sm3ReO7crystallizes in the orthorhombic system with unit cell dimensionsa= 10.736(5),b= 7.392(3), andc= 7.519(3) in space groupCmcm(No. 63) withZ= 4. The structure consists of ReO6octahedra, distorted SmO6octahedra, and SmO8prisms that are interconnected to each other to form a three-dimensional network. Rhenium has the formal oxidation state of +5 but no metal–metal bond is observed in this compound. The observed magnetization in the temperature range 4 K <T< 52 K is explained by a Curie–Weiss law modified by a temperature independent Van Vleck paramagnetism of samarium (3+).