CRYSTAL-CHEMISTRY OF THE ELEMENTS - MELTI NG TEMPERATURE, ATOMIC VOLUMES, FORMAL VALENCE, AND BOND VALENCES

Bond valence analysis has been performed on crystalline elements which occur in different modifications. For this purpose, the covalence of elements of main groups I to IV is set equal to group number N and to 8-N for elements of groups V to VIII. For d- and f-elements, empirical relations between melting temperature, atomic volume, and covalence w ere established and used for calculating the covalences. Bond valence parameters are calculated for 19 elements using the concept of geometr ical coordination which applies equally well to primary and secondary bonds.