The temperature dependence of heat capacity of Co 7/3 Sb 2/3 O 4 has been measured for the first time in the range from (6 to 337)K by precision adiabatic vacuum calorimetry. The experimental data were used to calculate standard thermodynamic functions, namely the heat capacity, enthalpy H°(T)−H°(0), entropy S°(T)−S°(0) and Gibbs function G°(T)−H°(0), for the range from T→(0 to 337)K. Additional spectroscopic studies were carried out to study the nature of the phase transition at T=60.3K. The structure of Co 7/3 Sb 2/3 O 4 is refined by the Rietveld method: space group F d3m, Z=8, a=10.3793(2)Å, V=1118.14(4)Å 3 . The high-temperature X-ray diffraction was used for the determination of temperature of high-temperature phase transition and coefficient of thermal expansion.