On the basis of factor analysis of data matrices containing 35 empirical and non-empirical parameters for 85 solvents (or a limited matrix of 20 parameters for 51 solvents), an orthogonal set of parameters with normed normal distribution has been suggested which characterizes influence of the solvents on chemical processes. A four-parameter equation has been suggested for description of the solvent effect in the form A = A0 + aAP + bBP + eEP + pPP, where AP, BP, EP, PP are newly introduced parameters expressing individual types of interactions between solvent and solute. A comparison has been carried out of these parameters with those defined earlier. The new set of parameters was tested with 22 examples taken from literature. The correlations obtained show higher or comparable agreement as compared with those carried out earlier. Values of the regression coefficients make it possible to discuss the reaction mechanisms from the point of view of solvent effects.