152-74-9 4,5,6,7-Tetrachloro-3',6'-dihydroxy-2',4',5',7'-tetraiodospiro(isobenzofuran-1(3H),9'(9H)-xanthen)-3-one Spiro(isobenzofuran-1(3H),9'(9H)-xanthen)-3-one, 4,5,6,7-tetrachloro-3',6'-dihydroxy-2',4',5',7'-tetraiodo-