July 19, 1951
Mr. Roger Hayward
920 Linda Vista
Could you during the next few days make some drawings. We need to get a paper off for publication immediately, because I have
learned that someone else (a Swede) is doing some closely similar work, and I think that we might as well publish our results
as obtained so far.
I would like to have drawings made of the structure of Na2Cd11, closely similar to those that you have already made for me in pastel. If you need to pick these up, please drop by the laboratory
and get them. There is, however, one difference, which I shall describe below - this involves an interchange of the six larger
atoms and six of the smaller atoms.
Also, the drawings to be made now should be line drawings from which cuts can be made - that is, black and white, line drawings,
with stippling or some other type of shading of the atoms.
The five drawings needed are, as before, a central atom surrounded by the skeleton of an icosahedron. Then the complex of
13 atoms surrounded by the skeleton of a pentagonal dodecahedron. Then two views of the rhombic triacontahedron, one a skeleton
drawing, as before, and the other a drawing showing 32 atoms at the corners of the triacontahedron. In this case, however,
12 of the 32 atoms are to be represented as somewhat larger than the others. These are the 12 atoms that are shaded red
in your pastel drawing. They are the atoms at the ends of the longer diagonals of the six rhombs that are in the six cube
faces. In order to make room for them, they might be moved out a little farther from the center of the rhomb than indicated
in your earlier drawings.
The fifth drawing is a drawing showing the structure obtained by placing one of these rhombic triacontahedra at each corner
of a cube, in such a way that the six rhombic faces are shared. Then an octahedron of six atoms (the same size as the smaller
atoms, now) is to be introduced at the center of the cube, in the same way as in your fifth pastel drawing, the only difference
being that these six atoms -are now the smaller atoms,
Mr. Hayward 7/19/51
and the others, as described before, at the ends of the long axes of the shared rhombic faces, are now the larger atoms.
If you have any questions about the nature of these drawings, please let me know. They are to accompany an article to be
published in the Proceedings of the National Academy of Sciences, The page here is 4 1/2 inches wide (length of the line)
and 7 1/4 high. I think that the first four drawings might be put on a single sheet, about 11 inches square, which could
then be reduced to 4 1/2 x 4 1/ 2. The second drawing could then be reduced to full page width, and the balls would come out
about the size as in the first drawing.