Gd-Sb system: standard enthalpies of formation of solid alloys and crystalstructure of Gd16Sb39

The data obtained in the investigation of Gd-Sb alloys are reported. This i nvestigation was performed using metallographic and X-ray diffraction analy ses and calorimetric measurements of the enthalpies of formation at 300 K. The values of Delta(f)H degrees (kJ/mol of atoms +/- 2) for the following c ompounds were obtained for the reaction in the solid state at 300 K: Gd5Sb3 : -110; Gd4Sb3: -116; GdSb: -120; Gd16Sb39: -78. The crystal structures of Gd5Sb3 (hP16-Mn5Si3 type), Gd4Sb3 (cI28-anti-Th3P4 type) and GdSb (cF8-NaCl type) have been confirmed. The crystal structure of the compound previousl y called "GdSb2" was determined by single-crystal methods and the compositi on Gd16Sb39 was found. (C) 2000 Elsevier Science Ltd. All rights reserved.