14 October 1953

Prof. G. V. Raynor

Department of Metallurgy

University of Birmingham

Edgbaston, Birmingham 15

England

Dear Professor Raynor:

I am writing to ask if you could give me your opinion of Dr. Naor, who applied to us for a grant of a post-doctoral fellowship, and gave you as a reference. He has now returned to Israel, but he said to me that he would like to be considered for appointment at some time in the future, and I should accordingly be glad to have your opinion of him.

I have read with interest your paper "The Crystal Chemistry of the Laves Phases," in the February 1953 Acta Crystallographica. Three or four years ago I carried through a detailed discussion of these intermetallic compounds, which has, however, remained unpublished. I reached the conclusion that in almost all of them there is some electron transfer, insuch a direction as to increase the valence of each of the atoms present: in MgZn₂, for example, from zinc to magnesium. This assumption, of course, accounts nicely for the unusually short interatomic distances, in comparison with those of the elements. It seems to me that there exists a great deal of evidence showing that electron transfer takes place in this direction, and also that the evidence in rapport of high valences for the transition metals is pretty strong.

Under separate cover I am sending you a reprint of my recent paper on the theory of ferromagnetism. This theory, which is much simpler than other theories of ferromagnetism that have been proposed, permits the calculation of magnetic properties of iron and other ferromagnetic substances without any assumptions - the interaction energies required can be obtained from spectroscopic data. The agreement with experiment is good; but it is obtained with use of the valency 6 for iron and corresponding valencies for the other transition elements. I think that the theory of ferromagnetism thus provides additional support for these valencies.

I should like also to say, with respect to the title of your recent paper, that we refer to these alloys as the Friauf phases.

Prof. Raynor -2- 14/10/53

You know that Dr. Friauf determined the structure of MgZn₂ and the structure of MgCu₂ several years before Laves became interested in these substances. Friauf obtained his doctor's degree in our laboratory nearly thirty years ago; he was trained in x-ray crystallography by Professor Roscoe G. Dickinson, from whom I also received my training. I have not discussed this question of nomenclature (Friauf phases versus Laves phases) with Friauf, but last year, while I was answering a letter that Laves had written to me about another matter, I mentioned it to him, and he replied that he too thought that it was proper to use the expression Friauf phases. I may say that I have not, so far as I remember, referred to the Friauf phases in any publication, because I think that it is probably better not to adopt the system that the Germans use of naming systems and substances after investigators. The Germans seem to think that the phases should be named not after the first investigator, but rather after the first German investigator. For example, they refer to the "Zintl phases," although I first determined the structure of a "Zintl phase" in 1923, several years before Zintl did any work on them.

I shall be grateful to you for your comments on Dr. Naor.

Sincerely yours,

Linus Pauling:W