What is [7-hydroxy-8-[(4-sulpho-1-naphthyl)azo]naphthalene-1,3-disulphonato(3-)]aluminium (CAS: 15876-47-8)?

[7-hydroxy-8-[(4-sulpho-1-naphthyl)azo]naphthalene-1,3-disulphonato(3-)]aluminium, also known as N-Sulphonated Alizarin Red S Aluminium Salt, is a complex organic compound. This compound has a unique structure that includes a naphthalene base with sulfur and azo groups, and aluminum as the metal ion. It is characterized by its bright red color and is soluble in water and organic solvents. This compound is often used in analytical chemistry for spectroscopic analysis and in the pharmaceutical industry for colorimetric assays.