IR spectroscopic investigation into rare earth ruthenates of pyrochlore structure

Pyrochlore structure of ruthenates of r.e.e. and yttrium have been studied by X-ray structural analysis and infrared-spectroscopy. Lattice parameters and X-ray densities for all the compounds of the A2Ru2O7 (A is r.e.e. or Y) series are calculated. Infrared absorption spectra of these compounds are compared to those of r.e.e. titanates, zirconates and hafnates of similar structure with the use of the data obtained by means of the theory of groups. It is suggested that the oscillations of pyrochlore structure crystals are non-characteristic. The oscillations displaying the greatest shift with the position of the element in the lanthanide series are largely those of the lanthanide polyhedron