Hi all, I have a question regarding the nomenclature of organic compounds. What is the significance of -5-yl in bicyclo[2,1,0]pent-5-ylbicyclo[3,3,0]octane ? In general, what is the significance of the # in -#-yl in compounds? Additionally, in (E)-1,2-diiodo-1methylcyclohexane, does the E indicate trans, whereas a Z would indicate cis? As in the two iodine atoms are on the first and second carbons, and they are both trans to each other (both axial)? Thanks guys!