On measuring the size of distortions in coordination polyhedra.
There is no unique index that measures the size of the distortion found in a coordination polyhedron because different indices can result in a different ordering depending on the mode of the distortion (i.e. the third and higher moments of the bond-length distribution). This paper proposes the increase in the average bond length as a suitable index as this is directly related to the increase in volume of the coordination polyhedron and hence of the unit cell. Some examples are discussed.
Brown
I David
ID
Brockhouse Institute for Materials Research, McMaster University, Hamilton, Ontario, Canada L8S 4M1. idbrown@mcmaster.ca