This set consists of sufficient parts to make models of benzene ethane ethene and ethyne. The atom cores are represented by the standard Molymod® atom parts and the atomic and molecular orbital parts by colour-coded matt or pastel-coloured pieces. These exclusively designed models help to demonstrate both sigma-bonding and pi-bonding and therefore the concept of electron delocalisation and orbital hybridisation.Atoms:2 x carbon (6 holes)8 x carbon (5 holes)2 x carbon (4 holes)18 x hydrogen (1 hole) Bonds:9 x carbon-carbon (oval shaped) sigma-bonds18 x carbon-hydrogen (pear shaped) sigma-bonds9 x pi-bonds (21 pink and 21 purple pieces).