Investigations of the dependence of the magnetic properties on the type of rare-earth metal in intermetallic compounds of the ThMn12-RFe11Ti and RFe10.5V1.5 type with a tetragonal crystal structure have established that the iron sublattice has uniaxial anisotropy, and spin-orientation phase transitions are found to occur in alloys where R = Nd, Tb, Dy, Er. Compounds SmFe12-yCoyTi and SmFe10.5-yCoyV1.5 are regarded as promising materials for permanent magnets with the least possible concentration of the rare-earth metal.