Letter from Linus Pauling to You-Chi Tang. July 5, 1951. Page 1  Larger Images / More Information. 1 p.  View Transcript

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Activity Listings

• Itinerary: San Diego State College, evening [Filed under LP Travel: Box #1.001, Folder 1.8]
• Letter from E. H. Volwiler, Abbott Laboratories, American Chemical Society to Alden H. Emery, American Chemical Society, RE: Writes that he is willing to appoint someone to represent the American Chemical Society in the Congress of Industrial Chemistry from the list LP provided, if they cannot find anyone else who is directly interested in industrial chemistry. [Letter from LP to Emery, June 30, 1950, Letter from Emery to LP, July 13, 1950] [Filed under LP Science: (American Chemical Society: Correspondence, 1950-1964), Box #14.006, Folder #6.1]
• Letter from Frances V. Benner, Special Assistant, American Chemical Society, to LP RE: Writes that LP’s proposed plan for the speaking tour of Iowa and Nebraska seems very agreeable, as long as the local American Chemical Society sections only have to finance the expenses connected with the tour itself and not his transportation to and from California since they are small and the financial burden may be too great otherwise. Also writes that for the formal announcement of his availability, they will need publicity material similar to those used for his recent southwest tour, and the copies are attached for his review. [Letter from LP to Benner, June 13, 1950, Letter from LP to Benner, July 17, 1950] [Filed under LP Science: (American Chemical Society: Correspondence, 1950-1964), Box #14.006, Folder #6.1]
• Letter from LP to N. A. Parkinson, Assistant to the Editor, Chemical and Engineering News, RE: Declines the offer because he has already agreed to prepare a review of this book for another journal. [Letter from Parkinson to LP, June 26, 1950] [Filed under LP Correspondence: (Chemical and Engineering News), #70.3]
• Letter from LP to W. H. Freeman RE: Informs him that Swift will be in the east from July 10 to 17, so Freeman will not get to meet him unless he changes the dates of his trip. [Filed under LP Correspondence: (W. H. Freeman and Company, 1950), #439.8]
• Letter from LP to William F. Leuenberger RE: Tells him not to be too discouraged about his difficulty in obtaining permanent employment in the US. States that the employment situation for organic chemists is poor. Tries to arrange a time to see Leuenberger. [Letter from Leuenberger to LP, June 25, 1950] [Filed under LP Correspondence: (L: Correspondence, 1950), #230.16]
• Memo from LP to Dr. Tang. [Filed under LP Correspondence: (T: Correspondence, 1950), #410.15]

  Dr. Tang

  Theory of the lead-thallium alloys

  I have developed a theory of the lead-thallium alloys, and similar binary alloys involving solid solutions with ordered structures. Perhaps you would be willing to carry out some calculations in connection with the theory.

  I assume that an ordered structure PbTl₃ or, taking into account the solid solution, Pb(Pb,Tl)₃, exists, with slightly greater stability than the disordered structure. The difference in stability - that is, in enthalpy, is small enough so that the entropy of mixing has to be taken into consideration, both for the liquid and for the crystalline phase.

  I assume that for each phase the enthalpy can be rep1resented as a linear function of the composition, in mole fraction, and that the entropy of mixing can be calculated by use of the ideal formula.

  I then write, for a given temperature T, the following expressions for the free energies, per mole, of the crystalline phase:

  S(c) = Hc -TS_c + h_c x RT x lnX - RD(3/4 - x)ln(3/4 - x) + RD 3/4 ln 3/4

  S(1) = H₁- TS₁ + h₁ x -RT x ln x -RT(1 - x)ln(1-x)

  For our purposes we may neglect the first three terms in the formula for S(l), and make a plot simply of the free energy of the liquid arising from the entropy of mixing. This is a loop, hanging down from the end-points, something like a catenary. Now let us represent the free energy of the crystal. The parts not dependent on the entropy of mixing can be represented by a straight line beginning at the left (corresponding to pure lead) slightly higher than the curve for the liquid, and dropping toward the right - it extends only as far as the point 75% Tl. The entropy contribution is a sort of catenary, only 3/4 as deep, hanging from the ends of this slant line. It intersects the curve for the free energy of the liquid at two places, or at any rate at one place.

• Note from M. C. Terry to LP RE: Asks LP to write Professor Harper because he is interested in sickle cell anemia [Letters from LP to Terry, June 26, 1950 and July 17, 1950] [Filed under LP Correspondence: (T: Correspondence, 1950), #410.15]