In this chapter a short summary of functions available in the 'chem' sublevel not discussed previously will be given.
The average structure of a crystal can be calculated using the command 'aver'. Occupancies, average positions and standard deviations for these positions are calculated. This command is not available when working with molecules. The neighbourhood of a given atom or molecule can be examined using the commands 'neig' and 'env'. The command 'neig' will use the currently stored neighbour definitions whereas 'env' will display all atoms found in a given distance from the chosen origin. Finally the conversion between atom index and unit cell / atom site can be made using the equation given in section 2.2 or via the command 'trans' in the 'chem' level of DISCUS.