Crystal structure reinvestigation and spectroscopic analysis of tricadmium orthophosphate

Acta Crystallogr E Crystallogr Commun. 2023 Nov 14;79(Pt 12):1155-1160. doi: 10.1107/S2056989023009775. eCollection 2023 Dec 1.

Abstract

Single crystals of tricadmium orthophosphate, Cd3(PO4)2, have been synthesized successfully by the hydro-thermal route, while its powder form was obtained by a solid-solid process. The corresponding crystal structure was determined using X-ray diffraction data in the monoclinic space group P21/n. The crystal structure consists of Cd2O8 or Cd2O10 dimers linked together by PO4 tetra-hedra through sharing vertices or edges. Scanning electron microscopy (SEM) was used to investigate the morphology and to confirm the chemical composition of the synthesized powder. Infrared analysis corroborates the presence of isolated phosphate tetra-hedrons in the structure. UV-Visible studies showed an absorbance peak at 289 nm and a band gap energy of 3.85 eV, as determined by the Kubelka-Munk model.

Keywords: cadmium phosphate; crystal structure; infrared spectroscopy; orthophosphates.