  On the basis of the first-principles evolutionary crystal structure
prediction of stable compounds in the Cu-F system, we predict two
experimentally unknown stable phases -- Cu2F5 and CuF3. Cu2F5 comprises two
interacting magnetic subsystems with the Cu atoms in the oxidation states +2
and +3. CuF3 contains magnetic Cu 3+ ions forming a lattice with the
antiferromagnetic coupling. We showed that some or all of Cu 3+ ions can be
reduced to Cu 2+ by electron doping, as in the well known KCuF3. Significant
similarities between the electronic structures calculated in the framework of
DFT+U suggest that doped CuF3 and Cu2F5 may exhibit high-temperature
superconductivity with the same mechanism as in cuprates.
