Gd–Sb system: standard enthalpies of formation of solid alloys and crystal structure of Gd16Sb39

The data obtained in the investigation of Gd–Sb alloys are reported. This investigation was performed using metallographic and X-ray diffraction analyses and calorimetric measurements of the enthalpies of formation at 300 K. The values of ΔfH° (kJ/mol of atoms ±2) for the following compounds 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 previously called “GdSb2” was determined by single-crystal methods and the composition Gd16Sb39 was found.