The thermal decomposition of n-butane at 442 °C.has been investigated analytically in the pressure range 4–13 cm. Up to 9% decomposition, the rates of formation of H2, CH4, C2H4, and C2H6 are independent of time; the dependence of the rates on butane pressure was approximately first order. The validity of the extrapolation procedure for obtaining the initial products was established, there being no significant variation in the composition of the products with extent of decomposition. In the nitric oxide fully inhibited reaction irreproducible rate data were obtained although the proportions in which the products are formed seemed to be roughly invariable. In view of this it is suggested that no very definite conclusions can be drawn from a comparison of the composition of the products of the normal and fully inhibited reactions. The heterogeneity of the fully inhibited reaction is stressed for the importance of this has not hitherto been sufficiently recognized. Attention is drawn to the apparent inefficiency of nitric oxide as an inhibitor.

A molecular orbital study of 2,3-dinaphthylene is reported, the ~nolecule being assumed to have a planar structure. The magnitude of the resonance energy shows that the interaction of the H electrons as a whole is quite strongly stabilizing. The bond orders have been conlputed and froin these the lengths of the bonds in the molecule have been deduced. The longest wave length in an allowed excitation probably arises from a transition between mobile electron levels of symmetry A l g -+ BIU and polarized in the direction of the long axis of the molecule. INTIiODUCTIONOn account of the cyclobutadiene structure which it contains, o-diphenylene has been much studied in the past, whereas the related dinaphthylenes on the other hand have received only scanty attention. Rosenhauer et al. (7) starting from a-naphthaquinone obtained a compound to which they assigned the structure I and from this by distillation with zinc dust claimed to have obtained a hydrocarbon which was formulated as 11.More recently Bell and Hunter (1) distilled I with zinc dust under a variety of conditions but failed to obtain 11.It is the purpose of this communication to record the results of theoretica1 calculations of the resonance energy, bond orders, and light absorption of 2,3-dinaphthylene in the hope that they may stimulate experimental work with which to compare them. CALCULATIONThe method of calculation, that of inolecular orbitals, is well known and need not therefore be described in detaiI. The electronic wave function of the T electrons is expressed as a linear combination of atomic orbitals and the secular equation found in the usual way (5) and solved subject to the following restrictions.(i) All the coulomb integrals are assumed to be equal and set equal to a.(ii) All resonance integrals Pi; between the T electrons on adjacent atoms are taken to be identical and set equal to 0 whereas all other resonance integrals are neglected.il!fanuscript