The crystal structure and magnetic and electrical properties of β-US2

Abstract

The crystal structure of β-US2 was refined using single crystal X-ray diffraction data. The lattice constants at room temperature are: a = 8.4803 Å, b = 7.1139 Å, and c = 4.1205 Å. The uranium atom is coordinated by nine sulphur atoms: two at a distance of 2.713 Å, two at 2.896 Å, two at 3.141 Å, one at 2.747 Å, one at 2.826 Å, and one at 2.888 Å. The magnetic measurements were carried out in the temperature range 4.2 to 1000 °K. The increase of the effective magnetic moment from 3.08 to 3.28 BM with temperature is explained on the assumption that the ground state is composed of four closely spaced singlets. The semiconducting character in the temperature range 4.2 to 650 °K was established with a forbidden gap ΔE≈1.2 eV. [Russian text Ignored].