The electrical properties of CuxZn1-x(HCOO)(2). 2H(2)O have been studied over a temperature range of 78-400 K. Results of the electrical conductivity, sigma(d.c.), sigma(a.c.), thermoelectric power, theta, relative permittivity, epsilon(r)＇, and dielectric loss factor, epsilon(r)", were reported. Anomalies in the physical properties have been observed at 220 K and at the vicinity of the decomposition temperature, and the mechanism of decomposition of solids has been studied. A random nucleation process (A(3)) was found to be the predominant decomposition mechanism for the system investigated. The effects of chemical composition and crystal structure on the physical properties are discussed.