Polycyclic Rings Bicycloalkanes: bicyclo[x.y.z]alkane(x≥y≥z) numbering starts at a bridgehead,proceeds around the largest bridge first,then around successively smaller bridges bicyclo[4.4.0]decane 二环[4.4.0]癸烷（十氢化萘) bicyclo[2.2.1.]heptane bicyclo[4.1.0]heptane bicyclo[3.2.1]octanebicyclo[4.4.0]decane bicyclo[2.2.1.]heptane bicyclo[4.1.0]heptane bicyclo[3.2.1]octane 二环[4.4.0]癸烷（十氢化萘） Bicycloalkanes: bicyclo[x.y.z]alkane (x  y  z) numbering starts at a bridgehead, proceeds around the largest bridge first, then around successively smaller bridges C C Cz Cy Cx Polycyclic Rings