화학공학소재연구정보센터
Inorganic Chemistry, Vol.54, No.3, 733-739, 2015
Synthesis, Crystal Structure, and TEM Analysis of Sr19Li44 and Sr3Li2: A Reinvestigation of the Sr-Li Phase Diagram
Two intermetallic phases in the Sr-Li system have been synthesized and structurally characterized. According to single-crystal X-ray diffraction data, Sr19Li44 and Sr3Li2 crystallize with tetragonal unit cells (Sr19Li44, I-42d, a = 15.9122(7) angstrom, c = 31.831(2) angstrom, Z = 4, V = 8059(2) angstrom(3); Sr3Li2, P4(2)/mnm, a = 9.803(1) angstrom, c = 8.784(2) angstrom, Z = 4, V = 844.2(2) angstrom(3)). The first compound is isostructural with the recently discovered Ba19Li44. Sr in Sr19Li44 can be fully replaced by Ba with no changes to the crystal structure, whereas the substitution of Sr by Ca is only possible within a limited concentration range. Sr3Li2 can be assigned to the Al2Zr3 structure type. The crystal structure determination of Sr19Li44 was complicated by multiple twinning. As an experimental highlight, an electron microscopy investigation of the highly moisture- and electron-beam-sensitive crystals was performed, enabling high-resolution imaging of the defect structure.