X-ray diffraction measurements on metallic and semiconducting hexagonal NiS

The crystallographic structure of hexagonal Nis has been determined at temperatures above and below the metal-semiconducting transition. The powder x-ray diffraction peak intensities were used to determine the atom positions in both phases. The symmetry of the unit cell is found to change from P6(3)/mmc(D-6h(4)) in the metallic phase to P6(3)mc(C-6v(4)) in the semiconducting phase.