COMPOSITION BASED ON SAMARIUM SESQUISULPHIDE, PREPARATION METHOD AND USE AS COLOURING PIGMENT

摘要

The invention concerns a composition based on samarium sesquisulphide, having a purity in samarium higher than 99 % relative to other rare earths and containing at least an alkaline or alkaline-earth element whereof a part at least is included in said sesquisulphide crystal lattice. In another embodiment, the composition is based on samarium sesquisulphide and at least one rare earth which is only trivalent and contains at least an alkaline or alkaline-earth element whereof a part at least is included in said sesquisulphide crystal lattice. In a third embodiment, the composition has a purity in samarium such that the cerium content is less than 1 %. The method consists in reacting samarium, trivalent rare earth and alkaline or alkaline-earth compounds with a gaseous mixture of hydrogen sulphide and carbon sulphide.