1,4-epoxy-1H-xanthene, 4,4a-dihydro-, (1R,4S)- InChI=1/C13H10O2/c1-2-4-10-8(3-1)7-9-11-5-6-12(14-11)13(9)15-10/h1-7,11-13H/t11-,12+,13?/m1/s rel-(1R,4S)-4,4a-dihydro-1H-1,4-epoxyxanthene