Zinc Phosphide Iodide (Zn₃PI₃) and Zinc Arsenide Iodide (Zn₃AsI₃): New Compounds with Disordered Defect Zincblende Structure

Abstract

New compounds, Zn3PI3 and Zn3AsI3, have been synthesized by the reaction of Zn3P2 or Zn3As2 with ZnI2 in evacuated sealed quartz tubes at 475°. They have disordered defect zincblende structures (space group [formula omitted]) in which three zinc atoms and one vacancy are disordered over four cation sites, and three iodine atoms and one phosphorus (or arsenic) atom are disordered over four anion sites. A high Debye parameter for the zinc atoms is attributed to vibrations in the direction of the vacancies. The lattice constants compare favorably with values calculated from atomic radii. Relationships among this new modification of the zincblende structure and other structures are discussed. The compounds reported are the only ones found in the pseudobinary systems studied; compounds with the antichalcopyrite structure have not been observed. Some chemical and physical properties of the new compounds are given. © 1963, American Chemical Society. All rights reserved.