The type and organization of the data used to describe molecular structures and properties is called a data structure. The data structure forms the basis for all graphical and/or computational operations applied to a molecule. The organization of the data structure can facilitate interaction between the user and program. Biopolymers are specifically recognized in the data structures of some programs.
Data requirements vary greatly between the various molecular modeling and graphics programs. Core requirements include chemical composition/bonding and molecular geometry. Many additional kinds of data are used for computational and graphical operations.
eata structures can be saved in whole or in part (depending on the program) to files. Such data files can be used to recreate a data structure in future sessions of the same program or, in some cases, to transfer molecular structures between programs.