Using the calorimetric method, the authors have investigated enthalpies of formation of the intermetallic compounds Fe0.67Zr0.33, Co0.5Zr0.5, Ni0.5Zr0.5, and Cu0.5Zr0.5 at 298°K as well as the integrated enthalpies of mixing of the liquid components of the ternary metallic alloys Ni1-x(Fe0.67Zr0.33)x, Ni1-x(Cu0.5Zr0.5)x and Ni1-x(Co0.5Zr0.5)x at 1873°K. The rules of variation of the enthalpy-of-formation values are discussed in the light of Miedema's theory.