We take the shortest distances between like atoms as the single bond lengths and the half the single bond lengths as the covalent radii. The bond lengths are measured mainly by X-ray diffraction, more rarely, by neutron diffraction on molecular crystals. By rotational spectroscopy can also get highly accurate values of bond lengths. A proposed new set of covalent atomic radii for most of the elements with atomic numbers up to 96 (Table 1) have been derived from correlating with and feeding back the various experiment results and fairly well agree with the data of bond properties and satisfactorily explain possibly all chemical observation (Zhang, 2010).