Daltonides and Berthollides

terms introduced by N. S. Kurnakov in 1912–14 to designate chemical compounds of constant composition (daltonides) and variable composition (berthollides). The term “daltonide” was proposed in memory of J. Dalton and the term “berthollide,” in memory of C. L. Berthollet. Most ordinary chemical compounds are daltonides; their compositions satisfy the law of definite proportions and the law of multiple proportions. Numerous instances of the formation of berthollides have been discovered in metallic systems and also among oxides, sulfides, carbides, hydrides, and others.