A SIMPLE ALGORITHM FOR THE ASSIGNMENT OF COORDINATION POLYHEDRON TO 7-COORDINATE SPECIES

An algorithm allowing the assignment of any seven-coordinate species t o one of the three coordination polyhedra usually describing this coor dination mode, D-5h pentagonal bipyramid, C-3v capped octahedron, and C-2v capped trigonal prism, is presented. Tests of this algorithm, imp lemented in a FORTRAN 77 program, on a set of 25 crystal structures co ntaining only monodentate ligands, taken from the Cambridge Structural Database, yield satisfactory results. Most of the complexes are close to only one of the three coordination polyhedra. Emerging structural trends in sevenfold coordination are briefly discussed.