Electronegativity Mulliken scale

While further details are left elsewhere (Magnasco, 2003), we shall content ourselves here to remark that the model atomic energy differences a2— i are seen to follow the Mulliken electronegativity scale (Coulson, 1961 McWeeny, 1979), an being the deepest atomic level for LiH,... 

The equation is valid for a given valence state. For instance, for trigonal boron compounds, a value of electronegativity can be defined for sp hybrid orbitals. Moreover, if the values of the ionization energy and electron affinity are expressed in MJ.moF , then the Mulliken electronegativity scale can be related to the Pauling scale by the relationship ... 

Distinguish between the Pauling and Mulliken electronegativity scales. 

Based upon a scale developed by Mulliken, electronegativity is the average of the ionization energy and the electron affinity ... 

Fig. 3.5 The Pauling (left-hand panel) and Mulliken (right-hand panel) electronegativities for the sp-valent elements. Note that the electronegativities scales run vertically downwards in order to emphasize the similarity with the free-atom energy levels in Fig. 2.16 and negative inverse core sizes in Fig. 2.13.

The problem has been resolved [69] by redefining electronegativity as the chemical potential of the valence state, calculated as the quantum potential of the valence electron, confined to its ionization sphere, i.e. x2 = h2/8mrl, expressed in eV. Whereas x corresponds to Pauling electronegativities, subject to simple periodic scaling, x2 corresponds to the Mulliken scale by the same type of operation. All of the many electronegativity scales in existence are simply related to the ionization radii, from which they ultimately derive. 

The electronegativity scale established by Pauling is not the only such scale, and the electronegativity of an atom A has been defined by Mulliken as... 

For example, fluorine has the Pauling electronegativity of 4.0 and a value of 3.91 on the Mulliken scale. A different approach was used by Allred and Rochow to establish an electronegativity scale. This scale is based on a consideration of the electrostatic force holding a valence shell electron in an atom of radius, r, by an effective nuclear charge,... 

Mulliken has arrived at an electronegativity scale by another and better way, obtaining good agreement with that of Pauling (Table 15). 

Equation [33] is Mulliken s definition of electronegativity, so the linear coefficient in the Taylor series is the electronegativity of the atom. Mulliken s definition is consistent with other electronegativity scales. The second-order coefficient, j J, is the hardness of the atom, For semiconductors, the hardness is half the band gap, and r] is an important property in inorganic and acid-base chemistry. " Physically, IP - EA is the energy required to transfer an electron from one atom to another atom of the same type,... 

R.S. MULLIKEN, A new electronegativity scale together with data on valence states and valence ionization potentials and electron affinities. J. Chem. Phys., 2, 782 (1934). 

The Mulliken scale was proposed by Robert S. Mulliken in 1934. On the Mulliken scale, numbers are obtained by averaging ionization potential and electron affinity. Consequently, the Mulliken electronegativities are expressed directly in energy units, usually electron volts. 

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