Atomic and Molecular Forces and Crystal Structure

Abstract

ONE of the most difficult problems in the theory of chemical valency is to form a clear picture of the attractive forces between similar atoms. Lewis and Langmuir, in their theory of the cubical atom, have each attributed the single valency bond to the mutual action between a pair of electrons, and Langmuir has recently pointed out (NATURE, April 29, p. 261) that, as regards chemical considerations, such a pair of electrons may be regarded as revolving in the same orbit. This idea is closely allied to Bohr's construction for the hydrogen molecule. It should, however, be pointed out that such a construction leads to a strong paramagnetic property for molecular hydrogen, unless the electron motions are compensated by rotation of the nuclear charges. Such compensation is scarcely likely, since the magnetic moment depends on the area of the orbit described, and evidence up to date points to a nuclear radius of small order compared with that of the electron orbit, even though the latter be small compared with the conventional radius of the atom.