Complex oxides of niobium and rare earth alkali, alkaline earth elements

Results of investigations and publication data on complex oxides of niobium (2-5) and alkali, alkaline earth, rare earth elements, scandium and yttrium were generalized. Detailed consideration was given to synthesis conditions, data of X-ray diffraction investigations, results of study of magnetic and electrical properties of these compounds with structures of perovskite, pyrochlore, ilmenite, tetragonal tungsten bronze. Character of interactions in solid phases in systems containing oxides of transition metals in intermediate oxidation states was analyzed. Side reactions preventing formation of compounds of elements in required oxidation state as well as ways of stabilizing unstable oxidation states were established