Yonghe Zhang ionocovalent theory applications (11)
American Huilin Institute, http://www.amhuilin.com/
Brown derived an alternative Lewis acid strength Sa  from Zhang electronegativity Xz.: “The average Lewis-acid strengths given in Table 2 can be seen to increase with the electronegativity. The correlation between the two quantities is shown in Fig.4 using the Zhang (1982) electronegativities that are specific to oxidation state. The line corresponds to the equation
Xz = 1.118Sa + 0.771”
which can be rewritten as
Sa = 1.18 Xz -0.653
where Xz is Zhang electronegativity, which gave Sa a solid definition and physical significance.
 I.D. Brown, Acta Cryst. B, 44, 545-553, 1988
 Y. Zhang, (1982). Inorg. Chem., 21, 3886.