Electronegativity (Mulliken-Jaffe): periodicity
R.S. Mulliken proposed an electronegativity scale in which the Mulliken electronegativity, ΧM is related to the electron affinity EAv (a measure of the tendency of an atom to form a negative species) and the ionization potential IEv (a measure of the tendency of an atom to form a positive species) by the equation:
ΧM = (IEv + EAv)/2
The subscript v denotes a specific valence state - so for trigonal boron compounds, a values of electronegativity can be defined for sp2 hybrid orbitals. If the values of IE and EA are in units of MJ mol-1, then the Mulliken electronegativity ΧM can be expressed on the Pauling scale by the relationship:
ΧM = 3.48[(IEv + EAv)/2 - 0.602]
Values presented here are largely from reference 1. Mulliken's proposals are to be found in references 2 and 3. Tables of values are also given in references 4 and 5 as well.
Mulliken-Jaffe electronegativities are tabulated for a number of orbitals as well as a consolidated set of values for various orbitals suitable to correlate with Pauling values:
- S.G. Bratsch, J. Chem. Ed., 1988, 65, 34.
- R.S. Mulliken, J. Chem. Phys., 1934, 2, 782.
- R.S. Mulliken, J. Chem. Phys., 1935, 3, 573.
- J.E. Huheey, E.A. Keiter, and R.L. Keiter in Inorganic Chemistry : Principles of Structure and Reactivity, 4th edition, HarperCollins, New York, USA, 1993.
- A.M. James and M.P. Lord in Macmillan's Chemical and Physical Data, Macmillan, London, UK, 1992.