Structural Chemistry of the Neptunium–Germanium Binary System

✍ Scribed by P. Boulet; D. Bouëxière; J. Rebizant; F. Wastin

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 398 KB
• Volume: 156
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.2000.9000

✦ Synopsis

The structural chemistry of the complete binary neptun-ium+germanide system has been investigated by means of X-ray di4raction. In addition to the well-known NpGe 3 (AuCu 3 type), at least 5ve new binary phases have been found. The crystal structure of NpGe 2؊x (defect ThSi 2 type), NpGe 2؊x (defect AlB 2 type), NpGe (USi type), Np 5 Ge 4 (Ti 5 Ga 4 type), and Np 5 Ge 3 (W 5 Si 3 type) have been re5ned from single-crystal and powder X-ray di4raction data. X-ray powder analyses by Rietveld-type pro5le re5nement revealed a small homogeneity range of the three 5rst phases, as usually observed with the rare-earth or uranium isotypic compounds, whereas Np 5 Ge 4 and Np 5 Ge 3 seem to be line compounds as the unit cell parameters were independent of the starting composition. The formation and the homogeneity range of these new phases are discussed, and the structural evolution is compared with the analogous uranium binary system.