Syonyms Name: 15880:1; C.I. Pigment Red 63, calcium salt (1:1); D & C Red no. 34; calcium (4Z)-3-oxo-4-[2-(1-sulfonatonaphthalen-2-yl)hydrazinylidene]-3,4-dihydronaphthalene-2-carboxylate; calcium 3-hydroxy-4-[(1-sulfonato-2-naphthyl)azo]naphthalene-2-carboxylate