The structural distortion of the anti-perovskite nitride Ca3AsN

The structure of the distorted anti-perovskite nitride Ca3AsN has been studied both by neutron powder diffraction at 305 and 15 K and by X-ray powder diffraction at room temperature. Ca3AsN is distorted to an orthorhombic cell with a and b ‡ a′ and c ∼ 2a′, where a′ is the lattice constant of the ideal undistorted cubic anti-perovskite. The distortion is produced by tilting of octahedra of Ca6N and results in six short and six long bond distances of the twelvefold coordinated As atom by Ca atoms.