This book deals with the synthesis, crystal growth and some of the physical properties of anhydrous Potassium tris(oxalato)ferrate(III) and Potassium sodium tris(oxalato)ferrate(III) with multifunctional applications. This book focuses on the crystal growth, structure, perfection, spectroscopic, optical, magnetic, dielectric and mechanical properties. The charge transfer mechanism is discussed using the quantum mechanical calculations of hyper polarizability and dipole moment. From the decomposition of iron oxide nanoparticles using XRD and spectroscopic techniques. Magnetic behaviuor of resulting polymorphs of iron oxide nanoparticles also discussed.