Cd8As7Cl: A Novel Pnictidohalide with a New Structure Type

✍ Scribed by Andrei V. Shevelkov; Ludmila N. Reshetova; Boris A. Popovkin

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 243 KB
• Volume: 134
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1997.7555

✦ Synopsis

A novel cadmium arsenide chloride, Cd 8 As 7 Cl (I), has been prepared by a two-step stoichiometric synthesis. It crystallizes in the cubic space group P23 (No. 195) with a unit cell parameter a ‫؍‬ 7.2660(10) A > (Z ‫؍‬ 1). The crystal structure has been solved based on single-crystal X-ray diffraction data ( -2 scans, leastsquares refinement on F 2 ) to R‫؍‬ 0.0258 and wR 2 ‫؍‬ 0.0435. I possesses a new type of crystal structure that is described as a distorted (not dense) primitive cubic packing of cadmium atoms, the cubic voids of which are filled by either arsenic or chlorine atoms or As-As pairs. The structure of I exhibits a position disorder for one-half of the cadmium atoms. The As-As pairs are cubically surrounded by eight cadmium atoms, the As-As separation being 2.43 A > , which is longer than in all known cadmium and mercury arsenide halides. Attempts to synthesize the corresponding bromide and iodide failed.