| 摘要 |
The composition is based on a samarium sesquisulphide, it exhibits a samarium purity with respect to other rare earth metals of greater than 99% and it comprises at least one alkali metal or alkaline earth metal element, at least a portion of which is included in the crystal lattice of the said sesquisulphide. According to another embodiment, the composition is based on a sesquisulphide of samarium and of at least one rare earth metal which is solely trivalent and it comprises at least one alkali metal or alkaline earth metal element, at least a portion of which is included in the crystal lattice of the said sesquisulphide. According to a third embodiment, the composition exhibits a samarium purity such that the cerium content is less than 1%. The process consists in reacting samarium, trivalent rare earth metal and alkali metal or alkaline earth metal compounds with a gaseous mixture of hydrogen sulphide and of carbon disulphide. |
