The C.I. 15625 is also called 1-Naphthalenesulfonic acid, 5-(2-(2-hydroxy-1-naphthalenyl)diazenyl)-, sodium salt (1:1); C.I. Acid Red 141, monosodium salt (8CI); Sodium 5-((2-hydroxynaphthyl)azo)naphthalenesulphonate. Its registry number is 5850-93-1. It also has other registry number which is 51790-50-2. Its systematic name is called sodium 5-[(2-hydroxy-1-naphthyl)azo]naphthalene-1-sulfonate. And the IUPAC name is called sodium 5-[(2E)-2-(2-oxonaphthalen-1-ylidene)hydrazinyl]naphthalene-1-sulfonate.

This chemical is soluble in hot water for the red, slightly soluble in cold water and ethanol. It is red purple in concentrated sulfuric acid, brown precipitate after dilution. It is yellow brown in concentrated nitric acid solution And it shows yellow brown in dilute sodium hydroxide solution. In aqueous solution, it will show brown precipitate after adding hydrochloric acid then it will become yellow after adding sodium hydroxide.

Physical properties about this chemical are: (1)#H bond acceptors: 6; (2)#H bond donors: 2; (3)#Freely Rotating Bonds: 4; (4)Polar Surface Area: 110.53 Å².

Uses: this chemical is mainly used for dyeing wool and silk. It can also be used for coloring paper and leather.

You can still convert the following datas into molecular structure:
(1)SMILES: [Na+].[O-]S(=O)(=O)c4cccc3c4cccc3N=Nc1c2ccccc2ccc1O ;
(2)InChI: InChI=1/C20H14N2O4S.Na/c23-18-12-11-13-5-1-2-6-14(13)20(18)22-21-17-9-3-8-16-15(17)7-4-10-19(16)27(24,25)26;/h1-12,23H,(H,24,25,26);/q;+1/p-1;
(3)InChIKey: XNQZZTFTKVKXOR-REWHXWOFAH