Linus Pauling: In J.A.C.S. 1927 I communicated a set of ionic radii, essentially theoretical, a little empirical
information put in them. And 1928 in P.N.A.S., the idea that you can hybridize the s and p orbitals for the carbon atom and get
tetrahedral orbitals explained the tetrahedral structure of carbon. Well, my calculations
then were too complicated that caused me to reach that conclusion. I didn't ever publish
them because they just were so complicated that I didn't have confidence in them.