A quantitative approach to the rationalization of some solution and solid state properties in a series of Co(III) organometallic derivatives is proposed, according to the following procedure. Five experimental quantities of 23 alkylcobaloximes, octahedral Co(III) complexes of type RCo(DH)(2)L (R = alkyl group, DH = monoanion of dimethylglyoxime, L = py) are analyzed by principal component analysis (PCA). These quantities are the Co-C and Co-N axial distances, displacements d of Co out of the coordination plane, log k’s for the displacement reaction of py, and chemical shifts of the gamma-C(py). A three-component PCA model, based on t(1), t(2), and t(3) scores, is significant according to cross validation criterion and accounts for 95% of the variance of the data set. The scores t(1), t(2), and t(3) are interpreted and discussed in terms of the electronic and steric properties of the R groups. With respect to the methyl derivative, t(1) values increase with an increase in both the number and the electron-donating ability of groups substituting the H methyl atoms. t(2) follows the increase in bulk of R, while t(3) is interpreted as a measure of the angular distortions at C alpha. Comparison with inductive, resonance, and steric parameters, derived from organic chemistry, is discussed. The t(1) score is approximately related to a linear combination of sigma(I) and sigma(R)(-), and t(2) is approximately related to the Taft steric constants. The three component model is applied to interpret kinetic, spectroscopic, structural, and thermodynamic data of cobaloximes and of Costa models with several L ligands, by using the equation Q(L) = a(0) + a(1)t(1) + a(2)t(2) + a(3)t(3), where Q(L) is the analyzed property in the series with a given L ligand, whereas a(i) represents the contribution of the t(i) parameter.