What is "trihydroxyanthraquinone"

n. (context organic compound English) Any of several isomeric organic compounds with formula C₁₄H₈O₅, formally derived from anthraquinone by replacing three hydrogen atoms by hydroxyl groups, and including several historically important dyes.

A trihydroxyanthraquinone or trihydroxyanthracenedione is any of several isomeric organic compounds with formula , formally derived from anthraquinone by replacing three hydrogen atoms by hydroxyl groups. They include several historically important dyes.

Wahl, Andre; Atack, F. W (1919) The Manufacture Of Organic Dyestuffs. G. Bell And Sons, Limited. Online version accessed on 2010-01-22.

Hugh Alister McGuigan (1921), An introduction to chemical pharmacology; pharmacodynamics in relation to chemistry. P. Blakiston's son, Philadelphia. Online version at archive.org, accessed on 2010-01-30.

The isomers may differ in the parent anthraquinone isomer and/or of the three hydroxyl groups.

In general there are 56 ways of choosing three out of the 8 hydrogens. However, if the underlying core is symmetrical, some of these choices will give identical molecules.