The Praseodymium Zinc Arsenide Pr3Zn2As6: Crystallizing with a Vacancy Variant of the HfCuSi2Type Structure

✍ Scribed by André T. Nientiedt; Wolfgang Jeitschko

• Book ID: 102607049
• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 189 KB
• Volume: 142
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1998.7979

✦ Synopsis

The new compound Pr 3 Zn 2 As 6 has been prepared by reaction of the elemental components in a NaCl-KCl flux. It crystallizes with a very pronounced subcell of the HfCuSi 2 type structure with two formula units PrZn 2/3 As 2 in the tetragonal subcell with a ‫؍‬ 400.6(1) pm and c ‫؍‬ 1019.7(4) pm. The ordered distribution of occupied and unoccum pied zinc positions leads to a three times larger cell. This structure was determined from four-circle X-ray diffractometer data of a twinned crystal: Pmmn, a ‫؍‬ 399.89(9) pm, b ‫؍‬ 1204.2(3) pm, c ‫؍‬ 1019.7(4) pm, Z ‫؍‬ 2, R ‫؍‬ 0.039 for 2663 structure factors and 39 variable parameters. Chemical bonding in this compound is briefly discussed.