The stick, or Deriding, model shows the carbon at the center of the tetrahedron (dark gray) with the hydrogens at each vertex (light gray); the covalent radius of each atom is approximated by the size of the color band. The ball-and-stick model provides similar information and is sometimes easier to visualize, and the true Van der Walls radius of the atoms is best shown by the space-filling model (shown with a ball-and-stick overlay). More complex hydrocarbons containing carbon chains can be formed by creating additional carbon-carbon bonds, as shown below for chains containing two, four and six carbon atoms you should note that in these structures, each carbon remains bonded to four other atoms (a valence of four) These molecules are also shown below in space-filling format s:+ When viewing organic molecules it is important to note that the rotation around carbon-carbon single bonds is generally very rapid (greater than 10. rotations per second)and the chain can assume a large number of conformations(termed conformational isomers)which are rapidly interconverted and cannot be separated under normal circumstances. A sample of conformational isomers for four- and six-carbon chains are shown belowThe stick, or Deriding, model shows the carbon at the center of the tetrahedron (dark gray) with the hydrogens at each vertex (light gray); the covalent radius of each atom is approximated by the size of the color band. The ball-and-stick model provides similar information and is sometimes easier to visualize, and the true Van derWalls radius of the atoms is best shown by the space-filling model (shown with a ball-and-stick overlay). More complex hydrocarbons containing carbon chains can be formed by creating additional carbon-carbon bonds, as shown below for chains containing two, four and six carbon atoms; you should note that in these structures, each carbon remains bonded to four other atoms (a valence of four). These molecules are also shown below in space-filling format: When viewing organic molecules it is important to note that the rotation around carbon-carbon single bonds is generally very rapid (greater than 106 rotations per second) and the chain can assume a large number of conformations (termed conformational isomers) which are rapidly interconverted and cannot be separated under normal circumstances. A sample of conformational isomers for four- and six-carbon chains are shown below: