68217-20-9;2,4-Ethanobiscyclopropa[4,5]cyclopenta[1,2,3-cd:1',2',3'gh]pentalene-5,6-dione,tetradecahydro-(1a.alpha.,1b.beta.,2.alpha.,2a.beta.,2b.alpha.,3a.alpha.,3b.beta.,3c.beta.,3d.beta.,4.alpha.,4a.beta.,4b.alpha.)-;2,4-Ethanobiscyclopropa(4,5)cyclopenta(1,2,3-cd:1',2',3'gh)pentalene-5,6-dione, tetradecahydro-, (1aalpha,1bbeta,2alpha,2abeta,2balpha,3aalpha,3bbeta,3cbeta,3dbeta,4alpha,4abeta,4b.