Formation enthalpy and structure of nonstoichiometric iron telluride

X-ray and calorimetric investigations of iron tellurides of variable composition FeTesub(1+x) (where 0.25<=x<=0.9) are conducted. It is stated that homogeneity region of iron ''monotelluride'' with the structure tending to the ''CdI2'' type at 973 K lies in the range from FeTesub(1.45) to FeTesub(1.65). A possible local symmetry of a certain ''becoming empty'' layer is presupposed for Fesub(5)Tesub(8)(FeTesub(1.60)) composition. Standard enthalpies of iron telluride formation are determined with the error 3350 kJ/kg-formula FeTesub(1.45)-347504; FeTesub(1.50)-35169.1; FeTesub(1.55)-37262.5; FeTesub(1.60)-39355.9; FeTesub(1.65)-38518.6 kJ/μg-formula in the high-temperature vacuum block calorimeter by the thermal effect of direct interaction reactions of elements taken in the corresponding stoichiometric quantities