Tungsten carbide has been shown to be an effective catalyst for a number of reactions that are readily catalyzed by platinum, but not at all by tungsten, and it was speculated that this behavior is due to changes in the electron distribution when carbon is added to tungsten. A test of this hypothesis, made by measuring the valence band x-ray photoelectron spectrum of tungsten carbide and comparing it with the spectra of tungsten and platinum, shows that, near the Fermi level, the electronic density of states of tungsten carbide more nearly resembles that of platinum than that of tungsten.

2-pyridyl radical, as suggested by Symons,24 then the agreement for both the N and H hyperfine coupling constants is much better. The observed spectrum shows three protons with a coupling constant of 4.3 G23 and a nitrogen coupling constant of 29.7 G.19 Examination of the calculated proton coupling constants for the pyridine cation, shown in Table I, reveals no correlation of the calculated and observed spectra. Further, the calculated nitrogen coupling constant for the cation is 52.5 G, which also does not agree with the observed 30 G. However, when we consider the 2-pyridyl calcula-(25) R. Strange and R. S. Drago, to be published.

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