Color reagents for barium

Synthetic and analytical studies on color reagents. XI

Abstract

Of several hundreds of compounds synthesized by the authors and their collaborator, ο-sulphono-ο'-hydroxyazo compounds are found to be color reagents for barium, among which, especially, the bisazo compounds of chromotropic acid are excellent. The colors of the reagents themselves are violet in a slightly acidic medium and their barium complexes are blue.