ERROR opening https://cactus.nci.nih.gov/chemical/structure/InChI=1S/2C5H8O2.Cu/c2*1-4(6)3-5(2)7;/h2*3,6H,1-2H3;/b2*4-3-;/file?format=sdf&get3d=True  -- InChI=1S/2C5H8O2.Cu/c2*1-4(6)3-5(2)7;/h2*3,6H,1-2H3;/b2*4-3-; could not be loaded.