A theoretical method for studying the inter-relation between the local structure and EPR spectra is established by diagonalizing the complete energy matrices. For [M(H2O)(6)]XCl6: Mn2+ (M = Zn, Mg, Cd, Ca; X = Pt, Sn) systems, the calculated results demonstrate that the local structures around the octahedral Mn2+ centers in the doped systems are very similar despite of the host crystals being different. Furthermore, it is shown that the EPR zero-field parameter D depends simultaneously on the local structure parameters R and h while (a - F) depends mainly on R, whether the doped systems are at liquid-nitrogen temperature or room temperature. (C) 2008 Elsevier B.V. All rights reserved.