On the bond lengths and interatomic distances in certain molecules and crystals

Abstract

The internuclear distances in the crystals of some of the elements at the absolute zero have been calculated, and the values are examined and compared with those in some molecules. In the first two short periods if the single bond length is denoted D , and the atomic number Z , a direct proportionality exists between D 2 and Z for the members of any one group from group IV to group VII. In groups IV to VII this proportionality extends to the corresponding elements of the first long period, so that, for example, the D 2 values for carbon, silicon and titanium are proportional to Z . In group III the D 2 value for boron and the square of the internuclear distance in the crystal of aluminium are proportional to Z , but the proportionality does no text end to scandium , and in groups I and II no proportionality exists between D 2 and Z . Simple whole-number relations are found between the squares of the internuclear distances in the earlier members of group II, and other regularities are pointed out. Evidence is also given for the hypothesis that simple whole number relations exist between the squares of the bond lengths of single, double and triple bonds of a given element.