Abstract: A simple relation is presented to calculate group electronegativity (X_G), viz., X_G=(2.6△_α^H-n)/5+2.6. △_α^H is the group deshielding parameter in ¹H NMR, proposed by author. n is the principal quantum number of center atom in the group. The relation of X_G with chemical shift parameter in ¹³C NMR is also drawn as X_G=(△_α^C+5n)/40+2. The resulting values of electronegativities for some 46 groups/atoms are similar to those obtained in previous papers, but calculated values from deshielding parameters of aromatic ring and anisotropic groups do not stand for their inductive effect. As a result,the principal quantum number of outer layer electrons in molecular orbital, maybe the deformation of MO, is a factor to influence the chemical shift.

Key words: NMR, Chemical shift, Deshielding paramter, Group dectronegativity, ¹H NMR, ¹³C NMR