Hostname: page-component-586b7cd67f-vdxz6 Total loading time: 0 Render date: 2024-11-22T21:20:28.310Z Has data issue: false hasContentIssue false

Charge transfer on the metallic atom-pair bond and the bond energy

Published online by Cambridge University Press:  27 June 2011

Thankappan Pillai Rajasekharan*
Affiliation:
Defence Metallurgical Research Laboratory, Hyderabad 500 058, India
Vummethala Seshubai
Affiliation:
School of Physics, University of Hyderabad, Hyderabad 500 046, India
*
a)Address all correspondence to this author. e-mail: [email protected]
Get access

Abstract

Following our recent report demonstrating the significance of the nearest-neighbor unlike atom-pair bond in metallic alloys, an equation for the energy of such a bond is presented in this study. The success of empirically derived Miedema’s equation in predicting the signs of the heats of formation of metallic alloys is explained. The negative contribution to the energy stems from the ionicity in the bond. The charge transfer on the bond, suggested by Pauling to establish electroneutrality, contributes the positive term which is quantified in this study. The value of Miedema’s empirically derived constant (Q/P)1/2 and the origin of the R/P term follow from the present model. It is shown that the energy of the atom-pair bond, calculated using the model, in the compounds of MgCu2 structure type are directly correlated to the experimental heats of formation of the compounds, and this fact enables the prediction of the heats of formation values for new compounds of the same structure type.

Type
Articles
Copyright
Copyright © Materials Research Society 2011

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1.Miedema, A.R., de Chatel, P.F., and de Boer, F.R.: Cohesion in alloys—fundamentals of a semi-empirical model. Physica 100B, 1 (1980).Google Scholar
2.Miedema, A.R., Boom, R., and de Boer, F.R.: On the heat of formation of solid alloys. J. Less-Common Met. 41, 283 (1975).Google Scholar
3.Boom, R., de Boer, F.R., and Miedema, A.R.: On the heat of mixing of liquid alloys—I. J. Less-Common Met. 45, 237 (1976).CrossRefGoogle Scholar
4.Miedema, A.R.: Energy effects and charge transfer in metal physics: Modelling in real space. Physica B 182, 1 (1992).CrossRefGoogle Scholar
5.Rajasekharan, T. and Girgis, K.: Structural information from Miedema’s theory for the heat of formation of intermetallic phases. Phys. Rev. B 27, 910 (1983).Google Scholar
6.Rajasekharan, T. and Girgis, K.: Information on the structures of intermetallic compounds from Miedema’s theory. J. Less-Common Met. 92, 163 (1983).Google Scholar
7.Rajasekharan, T. and Seshubai, V.: Importance of the atom-pair bond in metallic alloying. Intermetallics 18, 666 (2010).CrossRefGoogle Scholar
8.Kameswari, V.L., Seshubai, V., and Rajasekharan, T.: Prediction of concomitant structures in binary metallic systems from RG map: With MgCu2 structure type as an example. J. Alloy. Comp. 508, 55 (2010).Google Scholar
9.Kameswari, V.L.: Regularities in the structures adopted by intermetallic compounds in binary systems. Ph.D. Thesis, School of Physics, University of Hyderabad, Hyderabad, India, June 2008.Google Scholar
10.Pauling, L.: Electron transfer in intermetallic compounds. Proc. Natl. Acad. Sci. U.S.A. 36, 533 (1950).CrossRefGoogle ScholarPubMed
11.Slater, J.C.: Atomic shielding constants. Phys. Rev. 36, 57 (1930).CrossRefGoogle Scholar
12.Pauling, L.: The Nature of the Chemical Bond, 3rd ed. (Oxford and IBH Publishing, New Delhi, 1975), p. 92.Google Scholar
13.Jolly, W.L.: Modern Inorganic Chemistry, 2nd ed. (McGraw-Hill, New York, 1991), p. 62.Google Scholar
14.Mulliken, R.S.: A new electroaffinity scale; together with data on valence states and on valence ionization potentials and electron affinities. J. Chem. Phys. 2, 782 (1934).Google Scholar
15.Mulliken, R.S.: Electronic structures of molecules XI. Electroaffinity, molecular orbitals and dipole moments. J. Chem. Phys. 3, 573 (1935).CrossRefGoogle Scholar
16.Huheey, J.E.: Inorganic Chemistry, 2nd ed. (Harper & Row, New York, 1978), p. 167.Google Scholar
17.Pauling, L.: The nature of the interatomic forces in metals. Phys. Rev. 54, 899 (1938).Google Scholar
18.Pauling, L.: The Nature of the Chemical Bond, 3rd ed. (Oxford and IBH Publishing, New Delhi, 1975), pp. 393436.Google Scholar
19.Pauling, L.: The Nature of the Chemical Bond, 3rd ed. (Oxford and IBH Publishing, New Delhi, 1975), p. 93.Google Scholar
20.Gordy, W.: A new method of determining electronegativity from other atomic properties. Phys. Rev. 69, 604 (1946).Google Scholar
21.Pearson, W.B.: A Handbook of Lattice Spacings and Structures of Metals and Alloys (Pergamon Press, Oxford, 1967).Google Scholar
22.Villars, P. and Calvert, L.D.: Pearson’s Handbook of Crystallographic Data for Intermetallic Phases (American Society for Metals, Metals Park, OH, 1985).Google Scholar
23.Massalski, T.B.: Binary Alloy Phase Diagrams, 2nd ed. (ASM International, Materials Park, OH, 1990).Google Scholar
24.Zhu, J.H., Liu, C.T., Pike, L.M., and Liaw, P.K.: Enthalpies of formation of binary laves phases. Intermetallics 10, 579 (2002).Google Scholar
25.Mohallem, J.R., Vianna, R.O., Quintao, A.D., Pavao, A.C., and McWeeny, R.: Pauling’s resonating valence bond theory of metals: Some studies on lithium clusters. Z. Phys. D 42, 135 (1997).Google Scholar
26.Nissenbaum, D., Spanu, L., Attaccalite, C., Barbiellini, B., and Bansil, A.: Resonating-valence-bond ground state of lithium nanoclusters. Phys. Rev. B 79, 035416 (2009).Google Scholar
27.Harcourt, R.D. and Styles, M.L.: Model valence-bond studies of aspects of electron conduction along a linear chain of lithium atoms. J. Phys. Chem. A 107, 3877 (2003).Google Scholar