Neutron Diffraction Studies of NaUO₃

Abstract

Neutron diffraction studies have been made on a powdered NaUO₃ sample. It has been shown that an octahedron composed of six oxygen atoms around pentavalent uranium in this compound is distorted and four of six oxygen atoms are much closer to an uranium atom (U-O distance of 2.15 Å) than the other two (U-O distance of 2.24 Å). A unit of the UO₂⁺ ion does not exist in the crystal, though the pentavalent uranium has been expected to be in the form of UO₂⁺ as in the case of UO₂²⁺ of a hexavalent uranium ion. A neutron diffraction pattern at temperature of liquid helium has shown no appreciable difference from that at tem-perature of liquid nitrogen.