The bond valence parameters, R, and B, for C-O, N-O and La-O bonds have been evaluated. For V-O and Mo-O bonds in several coordination polyhedra, the bond valence parameters have been refined. For the first time, the parameter B has been found to be linearly dependent on the coordination number of the central atom in two series of polyhedra, LaOn (n = 7-12) and Moo (n = 5-7). (c) 2006 Elsevier B.V. All rights reserved.