IUPAC:2',7'-bis(2-carboxyethyl)-3',6'-dihydroxy-3-oxo-3H-spiro[2-benzofuran-1,9'-xanthene]-5-carboxylic acid; 2',7'-bis(2-carboxyethyl)-3',6'-dihydroxy-3-oxo-3H-spiro[2-benzofuran-1,9'-xanthene]-6-carboxylic acid
IUPAC:2',7'-bis(2-carboxyethyl)-3',6'-dihydroxy-3-oxo-3H-spiro[2-benzofuran-1,9'-xanthene]-5-carboxylic acid; 2',7'-bis(2-carboxyethyl)-3',6'-dihydroxy-3-oxo-3H-spiro[2-benzofuran-1,9'-xanthene]-6-carboxylic acid