PLATON Manual
Molecules and Residues
The concepts of molecules and residues are related but not
always synomymous within the PLATON realm. A residue is defined
as a part of the structure that is connected by intra-molecular
bonds only and is associated with a number. A structure may thus
contain one or more residues. Residues may be chemically
equivalent or chemically distinct. A molecule is defined as an
asymmetric part of the structure connected by intra-molecular
bonds only. Several molecules may join by crystallographic
symmetry into one residue. A particular molecule is designated by
a code: [nijk.rr] where n denotes the symmetry operation with
respect to the basic molecule, ijk the translation with respect
to 555 and rr the residue number. The structure of sucrose thus
consists of two molecules (e.g. [1555.01] and [2545.01]) but only
one residue.