Then came a shock. On March 1 — two weeks after Pauling submitted his new work but a month before it was published — a paper
appeared in the Physical Review that covered much of the same ground, including the idea of maximum overlapping of wave functions
to create the most stable bonds; a discussion of the relationship between ionic and covalent bonds; a description of how,
in compounds where there are several ways of drawing valence bonds, it was likely that "the real situation is . . . a combination
of the various possibilities, and on account of resonance the energy is lower than it would otherwise be"; and, most important,
an explanation of the tetrahedral bond in carbon. The author was John Slater, the young physicist whose work had helped to
inspire Pauling's breakthrough.
It looked at first as though Slater had beaten Pauling. But after reading it several times, Pauling found some important differences
in their work. Slater's paper, for one thing, was more descriptive than quantitative; it did not provide a way to get hard
numbers for bond strengths and lengths. Pauling dashed off a note to the Physical Review calling readers' attention to his
JACS paper's "very simple but powerful approximate quantitative treatment of bond strengths," briefly sketching his six rules,
and stressing that it was he who had first put forward the quantum-mechanical approach to tetrahedral binding in 1928. (Slater
had not referred to Pauling's earlier paper in his own work.) Pauling then quickly reviewed Slater's work and pointed out
ways in which his own ideas went further.
Click images to enlarge
Portrait of John C. Slater, 1952.
Directed Valence in Polyatomic Molecules. March 1, 1931.
"One could say that Pauling's 'failure' was to plant a lot of seeds, basic ideas, without working them out fully.... As soon
as Slater gets an idea he works it out to the end before he gets a new one. But that is also dangerous, of course because
you look at the trees and you don't see the forest...[Pauling] looks at the forest and lets other people...work out the specific
individual things in detail; he has a terrifically lively intellect, reading [Pauling's] paper, the information here is just
tremendous, the ideas flow out of the pen, and there are several lifetimes of work...to be done."