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Title: History of the application of the generalized Lewis acid-base theory to metals

Abstract

The history of my experiences with intermetallics has been found useful by students seeking my advice on which directions in science they should be emphasizing. In response to their question, I point to a mobile in my office consisting of seven hands pointing in different directions. Science comes up with so many unexpected developments that one's education should have a broad enough base to allow one to branch out in any direction to take advantage of unexpected opportunities. My historical presentation will be a personal account that I hope will serve as a guide to students. There have been many unexpected abrupt changes in my research.

Authors:
Publication Date:
Research Org.:
Lawrence Berkeley Lab., CA (USA)
OSTI Identifier:
6055136
Report Number(s):
LBL-26942; CONF-8809360-1
ON: DE89012992; TRN: 89-016556
DOE Contract Number:
AC03-76SF00098
Resource Type:
Conference
Resource Relation:
Conference: World material congress, Chicago, IL, USA, 24 Sep 1988; Other Information: Portions of this document are illegible in microfiche products
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; HISTORICAL ASPECTS; INTERMETALLIC COMPOUNDS; CHEMICAL BONDS; METALS; PLUTONIUM; ACTINIDES; ALLOYS; ELEMENTS; TRANSURANIUM ELEMENTS; 360104* - Metals & Alloys- Physical Properties

Citation Formats

Brewer, L. History of the application of the generalized Lewis acid-base theory to metals. United States: N. p., 1988. Web.
Brewer, L. History of the application of the generalized Lewis acid-base theory to metals. United States.
Brewer, L. 1988. "History of the application of the generalized Lewis acid-base theory to metals". United States. doi:. https://www.osti.gov/servlets/purl/6055136.
@article{osti_6055136,
title = {History of the application of the generalized Lewis acid-base theory to metals},
author = {Brewer, L.},
abstractNote = {The history of my experiences with intermetallics has been found useful by students seeking my advice on which directions in science they should be emphasizing. In response to their question, I point to a mobile in my office consisting of seven hands pointing in different directions. Science comes up with so many unexpected developments that one's education should have a broad enough base to allow one to branch out in any direction to take advantage of unexpected opportunities. My historical presentation will be a personal account that I hope will serve as a guide to students. There have been many unexpected abrupt changes in my research.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1988,
month =
}

Conference:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

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  • Titrations of palladium and rhodium by niobium have been carried out by determining the activity of niobium in alloys using high-temperature solid-electrolyte cells and by phase equilibria with oxides, carbides, and nitrides. The titration curve of niobium activity as a function of composition indicated a large crystal field effect with the two non-bonding pairs of palladium having substantially different base strengths. The non-bonding pair of rhodium is intermediate in base strength between the two pairs of palladium. At low concentrations of niobium, palladium is a stronger base, but rhodium becomes stronger at higher niobium concentrations. Additional measurements are in progressmore » for various combinations of 3d, 4d, and 5d elements to provide the information needed for an adequate crystal field model that could provide prediction of bonding capabilities. 16 refs.« less
  • The high thermodynamic stability of alloys composed of platinum group metals and group IVB and VB metals has been explained by an electronic interaction analogous to the Lewis acid-base concept for nontransition elements. The analogy is further demonstrated by the titration of palladium by addition of niobium. The activity of niobium in solid palladium was measured as a function of concentration by solid-state galvanic cells and study of the ternary oxide phase diagram. The galvanic cells were of the Pt/NbO/sub 2/, Nb/sub 2/O/sub 4.8//YDT/NbO/sub y/, Nb/sub (Pd)//Pt where the solid electrolyte is yttria-doped thoria (YDT). Ternary phase diagrams for themore » Pd-Nb-O and Rh-Nb-O systems were obtained by characterizing samples equilibrated at 1000/sup 0/C. The phase relationships found in the ternary diagrams were also used to derive thermochemical data for the alloys. Thermochemical quantities for other acid-base stabilized alloys such as Nb-Rh, Ti-Pd, and Ti-Rh were also measured.« less
  • The {gamma}-MoC phase with the hexagonal WC structure was prepared without the presence of metal stabilizers at temperatures below 1000{degree}C. This phase was found to be thermodynamically stable at low temperatures and decomposed to Mo{sub 2}C and graphite at 1400 K. Using equilibrium and thermodynamic data, the thermodynamic quantities of this phase were calculated. Oxide equilibration and solid-state galvanic cell experiments were used to study thermodynamic properties of binary Lewis acid-base stabilized transition-metal alloys. The activity of vanadium was determined in alloys of vanadium with platinum-group metals such as Rh, Pd, and Ir at 1000{degree}C. The activities of titanium inmore » titanium-iridium alloys and of niobium in Nb{sub 3}Ir were determined at 1400{degree}C. The ternary phase diagram of V-Pd-O at 1000{degree}C was obtained. Based on the vanadium-palladium results, a partial titration curve of palladium by vanadium was constructed. The excess partial molar Gibbs free energy of vanadium at infinite dilution was found to be {minus}36.4 kcal mol{sup {minus}1} at 1000{degree}C. Results are in agreement with the predictions of Brewer's theory of transition-metal alloy acid-base behavior.« less
  • The ..gamma..-MoC phase with the hexagonal WC structure was prepared without the presence of metal stabilizers at temperatures below 1000/sup 0/C. This phase was found to be thermodynamically stable at low temperatures and decomposed to Mo/sub 2/C and graphite at 1400 K. Using equilibrium and thermodynamic data, the thermodynamic quantities of this phase were calculated as S/sup 0//sub 298//R = 4.41 +/- 0.3 and ..delta..H/sub 298//sup 0//R = -3430 +/- 800 K. Part II. Oxide equilibration and solid-state galvanic cell experiments were used to study thermodynamic properties of binary Lewis acid-base stabilized transition metal alloys. The activity of vanadium wasmore » determined in alloys of vanadium with platinum group metals such as Rh, Pd and Ir at 1000/sup 0/C. The activities of titanium in titanium-iridium alloys and of niobium in Nb/sub 2/Ir were determined at 1400/sup 0/C. The ternary phase diagram of V-Pd-O at 1000/sup 0/C was obtained. Based on the vanadium-palladium results, a partial titration curve of palladium by vanadium was constructed. The excess partial molar Gibbs free energy of vanadium at infinite dilution was found to be -36.4 kcal mol/sup -1/ at 1000/sup 0/C. The results of this study are in agreement with the predictions of Brewer's theory of transition metal alloy acid-base behavior.« less
  • This paper describes a Bureau of Mines-devleoped method of dewatering clay slurries based on flocculation by high-molecular-weight polymers and water removal from the formed flocs using a trommel or hydrosieve. The exchange ion on the clays affects their dewaterability. Metal ions in solution and on the exchange sites of smectite clays are known to act as Lewis acids. Recent work has determined that these ions can be titrated with high-molecular-weight polymers. The relative acidity of the exchange ion and the basicity of the polymer determined by the new method give insight into the dewatering mechanism.