"The Resonating-Valence-Bond Theory of Metals." August 15, 1960. Page 1  Larger Images / More Information. 4 pp.  View Transcript

<   August  1960   > S M T W T F S   1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

Activity Listings

• Check from AHP to J.W. Robinson for $233.49.  [Filed under LP Biographical:  (Business and Financial:  Bank Statements and Canceled Checks, January 1960-December 1961), Box #4.026, Folder #26.1]  [Also filed under LP Biographical:  (Business and Financial:  Check Registers, 1957-1962), Box #4.076, Folder #76.4]
• Form: Registration Form for the Fifth General Assembly, International Congress and Symposia. [Filed under LP Speeches: (Speeches by LP, 1960) Box #1960s2 Box #1960s2.12]
• Letter from Aubrey Williams to Senator Lyndon B. Johnson RE: Shares that it would be a greater victory for the communists if they put men in prison for working for a sane nuclear policy. [Filed under LP Biographical: (Correspondence re: Senate Internal Security Subcommittee, 1960), Box #2.019, Folder #19.1]
• Letter from B.R. Willeford to Senator Thomas J. Dodd RE: Asks him to withdraw his request for LP to divulge the names of those who helped circulate his petition. Shares that he fails to see how this information could contribute to the legislative purposes of the subcommittee. [Filed Under LP Biographical: (Correspondence re: Senate Internal Security Subcommittee, 1960), Box #2.018, Folder #18.1]
• Letter from Don Stewart, to LP. RE: Has made a 3-D periodic chart. Asks for more information on the periodic chart. [Letter from LP August 31, 1960] [Filed under LP Correspondence: (S: Correspondence, 1960) #381.1]
• Letter from Findlay E. Russell, College of Medical Evangelists, to LP. RE: Thanks him for his letter. Informs him that he has received a letter from Senator Kuchel. [Filed under LP Correspondence: (C: Correspondence, 1960) Box #75 Folder #75.3]
• Letter from LP to Lloyd T. Chandler and Christina Wahrolen RE: Thanks them for the letter and enclosed check. Shares his court action against the subcommittee. [Letter from Chandler and Wahrolen to LP July 19, 1960] [Filed under LP Biographical: (Correspondence re: Senate Internal Security Subcommittee, 1960), Box #2.018, Folder #18.1]
• Letter from LP to Monsieur Jacques Savary RE: Thanks him the copy of the article they published discussing his hearing before the committee. [Filed under LP Biographical: (Assorted Materials re: Senate Internal Security Subcommittee, 1960-1964), Box #2.020, Folder #20.6]
• Letter from LP to Mrs. William Taylor. RE: Asks what day Armistice Day is. [Letter from Taylor July 28, 1960, undated] [Filed under LP Correspondence: (T: Correspondence, 1960) #411.5]
• Letter from LP to Myrtice G. Pomeroy. RE: Is unable to speak at the Friends Meeting in Vienna. [Letter from Pomeroy August 2, 1960] [Filed under LP Correspondence, (P: Correspondence, 1960) #314.1]
• Letter from LP to Robert Sterling RE: Shares his issues with the Managing Editor of the New York Times. Thanks him for sending his correspondences. [Letter from Sterling to LP July 18, 1960]  [Filed under LP Biographical: (Correspondence re: Senate Internal Security Subcommittee, 1960-1981), Box #2.017, Folder #17.4]
• Letter from LP to Sheila Barrett Brown RE: Thanks her for writing to the Editor of the New York Times and sending a copy along with the reply from the editor. States he did not like the reply and would like some sort of apology from the editor about the errors. [Filed under LP biographical: (Correspondence re: Senate Internal Security Subcommittee, 1960-1981), Box #2.017, Folder #17.4]             
• Letter from Lee W. Gildart and Thomas E. Johnson, University of Kentucky, to LP. RE: Asks him to read and criticize the enclosed resume of their work. [Letter from LP August 24, 1960] [Filed under LP Correspondence: (G: Correspondence, 1960) Box #141 Folder #141.4]
• Letter from Milton Harris, the Gillette Company, to LP. RE: Is delighted that LP will be able to talk before the Washington Section of the American Chemical Society on April 13th, 1961. Recalls the time they met at a dinner at Sterling Hendricks' home. [Filed under LP Speeches: (Speeches by LP, 1961) Box #1961s, Folder #1961s.11]
• Letter from Mrs. B. Richardson, to LP. RE: Is disgusted at the reported attitude of certain instruments of the American Government.  [Filed under LP Correspondence: (R: Correspondence, 1960) # 342.1]
• Letter from P. Healy, Branch Secretary, Waterside Workers' Federation of Australia, to LP RE: Encloses a copy of the letter forwarded to President Eisenhower. Convey their appreciation for his efforts. [Letter from LP to Healy August 20, 1960] [Letter from Healy to Eisenhower August 15, 1960] [Filed under LP Biographical: (Correspondence re: Senate Internal Security Subcommittee, 1960), Box #2.019, Folder #19.1]
• Letter from P. Healy, Branch Secretary, Waterside Workers' Federation of Australia, to President D. Eisenhower RE: Informs him of their views in regard to the summoning of LP before a "witch hunting" committee. [Filed under LP Biographical: (Correspondence re: Senate Internal Security Subcommittee, 1960), Box #2.019, Folder #19.1]
• Letter from Richard S. Kasel, to LP. RE: Gives a quote on a 1960 Ford 8 cylinder 4 door. [Filed under LP Correspondence: (H: Correspondence, 1960) Box #167 Folder #167.5]
• Memorandum from Walter M. Meier, to LP. RE: Gives two short statements regarding his research at CIT. [Filed under LP Correspondence: (M: Correspondence, 1960) # 258.2]
• Newsletter: "Announcing the Formation of the..National Committee to Abolish the Un-American Activities Committee", August 15, 1960. [Filed Under LP Biographical: (Civil Liberties- House Un-American Activities Committee, 1961-1963. ( House Committee on Un-American Activities)), Box #2.042, Folder #42.20]
• Newspaper Clipping: "The World's People Mourn Hiroshima and Vow: No More!", New York National Guardian, August 15, 1960. [Filed under LP Biographical: (LP Scrapbooks, 1956-1960), Box #6.007, Folder #7.701]
• Note to Self, Handwritten by LP, RE: LP writes about some stocks. Says "WHF [W.H. Freeman] asks if I've would go to $40 or $45 a share... I said yes if provision for WHF's buying back in 3 yrs. was deleted. [Filed under LP Safe: Drawer #2, Folder #2.009]
• Program: International Union of Crystallography, Fifth General Assembly International Congress and Symposia. 15-24 August, 1960. [Filed under LP Speeches: (Speeches by LP 1960) Folder #1960s2 Box #1960s2.12]
• Proposal from Dorothy Redlich RE: Proposes the method she wants to use to study the biochemical basis of mental deficiency. LP handwritten notes; "Runs till 30 June 1961," "15 Aug. 1960," "Dr. Shaw, Dr. Perry. Doubt that it is practical for us. We couldn't get liver or brain. Other tissues less signif." [Filed under LP Science: (Orthomolecular Medicine and Mental Health: Materials re: Ford Foundation grants for the study of mental disorders, 19555-1966), Box #11.089, Folder #89.11]
• Typescript: "Second Statement by Linus Pauling," (re: motion for interlocutory stay and/or interlocutory injunction). [LP Biographical: (Statements and Correspondence Made Public re: Senate Internal Security Subcommittee, 1960), Box# 2.015, Folder# 15.6] and [Filed under LP Biographical: Pauling v. Bellingham Publishing Company, 1960-1962: Box #3.002, Folder # 2.1]
• Typescript: 'The Resonating-Valence-Bond Theory of Metals' by LP. [Filed under LP Speeches: (Speeches by LP, 1960) Box #1960s2 Box #1960s2.12]

  THE RESONATING-VALENCE-BOND THEORY OF METALS

  By Linus Pauling

  California Institute of Technology, Pasadena, California

  The resonating-valence-bond theory of metals was developed during the period 1933 to 1948. It is an extension to metals and alloys of the chemical structure theory developed by chemists for organic and inorganic substances in general during the century from 1860 on. Some substances, such as propylene, can be represented satisfactorily by a single valence-bond structure; for this molecule the structure involves one arrangement of a carbon-carbon double bond, a carbon-carbon single bond, and six carbon-hydrogen single bonds. For other substances, such as benzene, more than one arrangement of the bond is used.

  The metals may be placed in the class of electron-deficient substances, together with the boranes, ferrocene and related substances, hexa-kaidekamethyltetraplatinum, and elementary boron. The characteristic feature of these substances it that some of the atoms have a larger number of stable valence orbitals than valence electrons. In general, some of the atoms of electron-deficient substances have a ligancy that is greater than the number of bond orbitals; there is some evidence that it la the atoms adjacent to an electron-deficient atom that are induced to increase their ligancy to a value greater than their orbital number. Chemical structures for electron-deficient substances an be found by assigning the electron-pair bonds (or one-electron bonds) to the available positions in all possible ways; that is, by writing all possible structures for the substance (with only one arrangement of the nuclei), and then superimposing those structures, as in the general theory of chemical resonance. This theory accounts in a satisfactory way for observed interatomic distances and other structural features of electron-deficient substances.

  Magnetic properties and observed bond lengths for metals have indicated that 0.72 orbital per atom in a metal (that is, about one orbital for each of three-quarters of the atoms) is to remain unused In the allocation of bonds. This orbital, called the metallic orbital, seems to be responsible for metallic properties, presumably in that it permits the unsynchronized resonance of valance bonds through a metal crystal, thus leading: to electrical conductivity and other metallic properties. It is the metallic orbital that permits the classification of metals as electron-deficient substances.

  The analysis of observed interatomic distances and saturation magnetic moments of transition metals in terms of the resonating-valence-bond theory, together with the proposal made by Zener about interaction between atomic electrons and bonding electrons, has led to the following description of metallic iron (Pauling, Phys. Rev. 54, 899 (1938), Proc. Nat. Acad. Sci. U.S. 39, 551 (1953)). Two of the eight electrons of each iron atom occupy 3d orbitals, with parallel spins. These electrons, which may be called atomic electrons, do not participate in electrical conduction. The remaining six electrons are bonding (conduction) electrons. The orbitals that they occupy are hybrid orbitals, which, together with the metallic orbital, are made of the three remaining 3d orbitals, the 4s orbital, and the three 4p orbitals (with, of course, acme contributions of less stable orbitals). The spin-spin Interaction between the atomic electrons and the conduction electrons uncouples approximately 0.22 electrons in the conduction band per atom. It is this interaction that gives rise to ferromagnetism in this metal (Zener).

  The iron atom in the metal may hence be described as being based upon the configuration 3d54s4p2, in the sane way that the carbon atom in diamond is described en being baaed upon the configuration 2s2p3. In each ease this description represents only an approximation.

  The description of the electronic structure of other metals is similar. For example, for nickel there are ten electrons outside of the argon shell. If the assumption is made that the metallic orbital, 0.72 per atom, must be preserved, there are only 8.28 orbitals available for occupancy by the ten electrons. Six of these orbitals are occupied by conduction electrons, as in iron. The remaining 2.28 orbitals contain 2.28 electrons with parallel spin and 4 - 2.28 = 1.72 with antiparallel spin; the resultant magnetic moment of the atomic electrons is then 0.56. The saturation magnetic moment for nickel, 0.61, is due to this atomic moment plus the small moments of the uncoupled conduction electrons and the orbital contribution.

  Two decades ago the electronic structure of iron was usually discussed on the basis of the band theory by stating that about 0.22 electron per atom had been promoted to the 4s conduction band. leaving a hole of 2.22 in the 3d shell; that is, that the configuration could be described as 3d7.78s0.22. During recent years the description has been changed; for example, Mott and K.W.H. Stevens (Phil. Mag. 2, 1364 (1957)) describe metallic iron (body-centered) as having two 3d electrons with parallel spin in non-conducting states, and the remaining six electrons, conduction electrons, occupying orbitals formed of 3d, 4s, 4p, and higher functions, with about 0.2 uncoupling of electron spins by the Zener interaction. This description is essentially identical with that of the resonating-valence-bond theory. However, Mott and Stevens also say that the face-centered nickel crystal contains a mixture of ions 3d9 and 3d10 with 0.7 holes, and 0.7 electrons In the 4s orbital forming the conduction band. I feel that the striking gradual change in magnetic moments, interatomic distances, and other properties of the transition metals end their alloys with change In average atomic number provides strong support for the belief that the electronic structures are closely similar in such a sequence, rather than greatly different, and that the description provided by the resonating-valence-bond theory is a satisfactory one for nickel as well as for iron.

  In interatomic compounds and other alloys there may be a transfer of electrons from atoms of one kind to those of another kind. This transfer is usually in the direction such as to neutralize the polarity of the bonds themselves that is correlated with the electronegativity difference of the atoms and such as to increase the number of bonding electrons. Alloys in which electron transfer occurs are often much denser, harder, and stronger than their components.