The molecule is the conjugate base of magnesium protoporphyrin, formed by deprotonation of the carboxyethyl groups at C-13 and C-17. It is the principal species at pH 7.3. It is a conjugate base of a magnesium protoporphyrin.
magnesium;3-[18-(2-carboxylatoethyl)-7,12-bis(ethenyl)-3,8,13,17-tetramethylporphyrin-21,23-diid-2-yl]propanoate