A table of additive covalent radii for tetrahedrally coordinated crystals is obtained by simple quantum-mechanical considerations using the bond lengths of the four diamond-type crystals and only two free parameters. The 39 bond lengths so obtained agree with experiment with an rms error of less than 1%. The extension of these considerations to other crystal structures and to molecules is considered. These radii should be useful for estimating lattice distortions produced by isoelectronic impurities.

• Received 5 March 1970

DOI:https://doi.org/10.1103/PhysRevB.2.2160