A new compound Sr2FeWO6 has been synthesized by solid state sintering. The phase transition of this compound was investigated by means of differential scanning calorimetry (DSC), X-ray powder diffraction, precise measurement of lattice parameters and other methods. It has been discovered that the compound has a displacive phase transition of the first order at (360±5)°. The low temperature phase, α-Sr2FeWO6, belongs to tetragonal crystal system, with space group I4/m; its lattice parameters at room temperature are: a=b=0.55702 nm, and c=0.79094 ran, the measured density is Dm = 6.93 g/cm3, and each unit cell contains two formula weights. The high temperature phase, β-Sr2FeWO6, belongs to the cubic system, with space group Fm3m and the lattice parameter is a=0.7939nm at 400°; z=4. The calculated density is Dx =6.780 g/cm3. The crystal structures of α-Sr2FeWO6 and β-Sr2FeWO6 were also determined by means of the X-ray polycrystal diffraction method. The phase transition mechanism and the temperature
