VERFAHREN ZUR HERSTELLUNG VON ZUSAMMENSTELLUNGEN AUF BASIS DER SELTENEN ERDMETALLE

摘要

The invention relates to new compositions based on rare-earth metal sesquisulphides M2S3, which can be used especially as colouration pigments, these compositions being characterized by the fact that they contain alkali metal and/or alkaline-earth metal elements for part at least included in the crystalline network of the said sesquisulphides. The process for their preparation consists in heating at a suitable temperature, under a non-oxidizing and preferably reducing atmosphere, an initial mixture containing a rare-earth compound, sulphur and a compound of an alkali metal and/or alkaline-earth metal element.