ERROR opening https://cactus.nci.nih.gov/chemical/structure/InChI=1S/2C4H8N2O2.Cu/c2*1-3(5-7)4(2)6-8;/h2*7-8H,1-2H3;/q;;+2/p-2/file?format=sdf&get3d=True  -- InChI=1S/2C4H8N2O2.Cu/c2*1-3(5-7)4(2)6-8;/h2*7-8H,1-2H3;/q;;+2/p-2 could not be loaded.