Structural study of room temperature synthesized nickel thiophosphate a–NiPS₃

A structural study using x-ray diffraction and simulation calculations was performed on a–NiPS₃, the highly disordered phase of the nickel thiophosphate, synthesized through a soft chemistry process. The structure of the wet gel is shown to be entirely amorphous; its x-ray pattern exhibits diffusion peaks according to the disordered anionic network. For the powdered samples, measurements of the width of the diffraction lines show that there are small crystallized c–NiPS₃-type crystallites with a volume V equal to (25 × 25 × 40) ų (i.e., 4a × 3b × 6c in terms of volume cell). The simulation calculations of the x-ray diagrams have indicated that the stacking of these crystallites is quite imperfect: the suggested crystallite structures must contain rotated or shifted layers.