Preparation of γ-Gd2S3 via thermolysis of Gd[S2CN(C4H8)]3·phen coordination

Pure γ-Gd2S3 was synthesized by the thermolysis of a single Gd[S2CN(C4H8)]3phen complex precursor in a flow of argon carrier gas containing sulfur vapor. The complex precursor was decomposed into amorphous Gd2S3 and carbon at about 350 C. Crystalline γ-Gd2S3 could be achieved at temperature exceeding 600 C, and the obtained γ-Gd2S3 presented a very high degree of crystallinity at 800 C. Carbon prevented the formation of Gd2O2S impurity in the preparation of γ-Gd2S3. However, the carbon blackened the product. At temperature ≥1000 C, the residual carbon impurity could be efficiently removed by introducing sulfur into the system for the volatile CS2 could be formed in situ via the reaction of sulfur with the deposited carbon. In the meantime, S also promoted the crystallization of γ-Gd2S3 remarkablely.