Аннотация:In this work, we synthesize and investigate lower technetium hydrides at pressures up to 45 GPa using synchrotron x-ray diffraction, reflectance spectroscopy, and ab initio calculations. In the Tc-H system, the hydrogen content in TcHx phases increases when the pressure rises, and at 27 GPa we found a hexagonal (hcp) nonstoichiometric hydride TcH1.3. The formation of technetium hydrides is also confirmed by the emergence of a reflective band at 450–600 nm in the reflectance spectra of TcH1+x samples synthesized at 45 GPa. On the basis of theoretical analysis, we propose crystal structures for the phases TcH0.45±0.05(Tc16H7) and TcH0.75±0.05 (Tc4H3) previously obtained at 1–2 GPa. Calculations of the electron-phonon interaction show that technetium hydrides TcH1+x (x=0–0.3) do not possess superconducting properties due to low electron-phonon interaction parameter (λ∼0.23).