spiro[phthalan-1,9'-xanthen]-3-one, spiro[2-benzofuran-3,9'-xanthene]-1-one, Fluoran, Spiro(phthalan-1,9'-xanthen)-3-on, Spiro(isobenzofuran-1(3H),9'-xanthen)-3-one, Spiro[isobenzofuran-1(3H),9‘-[9H]xanthen]-3-one, Spiro[isobenzofuran-1(3H),9'-[9H]xanthen]-3-one, 3H-spiro[2-benzofuran-1,9'-xanthen]-3-one