In an adiabatic low-pressure calorimeter, the temperature dependence of the standard molar heat capacity of paramagnetic dicarbonyl rhodium complex with o-semiquinone (CO)(2)Rh(SQ) has been determined in the range from T = (6 to 3 55) K mainly with an accuracy of about 0.3%. Over the ranges from T= (205 to 234) K, T= (266 to 315) K and T= (316 to 345) K physical transformations have been revealed and their enthalpies and entropies have been estimated. The experimental data were used to calculate the thermodynamic functions C-p,m(o)/R, Delta H-T(0)m(o) (R . K), Delta S-T(0)m(o)/R and Phi(o)(m) = Delta S-T(o)m(o) - Delta(T)(o)/H-m(o)/T (where R is the universal gas constant) between T = (0 and 355) K. The fractal dimension D in the heat capacity function of the fractal variant of Debye heat capacity theory has been evaluated. (C) 2005 Elsevier Ltd. All rights reserved.