oxonitride formula lntaon2 with high brilliance, procedures for their production and their use

摘要

Oxonitrides (oxynitrides) having a perovskite structure of the general formula LnTaON2, where Ln is a rare earth element, are known and can be prepared by ignition of a powder mixture comprising a Ta(V) compound and an Ln compound in an ammonia-containing reducing atmosphere. According to the invention, such oxonitrides having increased colour brilliancy (brilliance) can be prepared by the powder mixture to be ignited additionally containing a mineraliser selected from the group consisting of alkali metal or alkaline earth metal halides, Na3AlF6, Na2SiF6, AlF3 or the ammonia salts of carbonic acid or a monocarboxylic or dicarboxylic acid having from 1 to 4 carbon atoms in an amount of from 0.1 to 10 parts by weight, based on 1 part by weight of the mixture comprising the Ta and Ln compound. Oxonitrides of the formula LnTaOn2, in particular oxonitrides prepared according to the invention, can be used as yellow-orange to red-brown colour pigments. IMAGE