I 3787 (OTTO) Iron yttrium oxide, 99.9% Cas no 12063-56-8 - used in superconductors. I 3787 (OTTO) Iron yttrium oxide, 99.9% Cas no 12063-56-8 - used in filters, transmitters, transducers, solid state lasers in faraday rotators and in non-linear optics. It finds application in polymers, textiles, fuel cell layers, composites and solar energy materials, bio nano materials and bio sensors. I 3787 (OTTO) Iron yttrium oxide, 99.9% Cas no 12063-56-8 - used in the preparation of fuel cells and solar energy materials.