Magnetochemistry is a branch of science that examines the interrelationship between a magnetic field and atomic or molecular structure as it is concerned with the magnetic properties of chemical compounds. Magnetic properties arise from the spin and orbital angular momentum of the electrons contained in a compound. Compounds are diamagnetic when they contain no unpaired electrons. This book is specifically written for the graduates and postgraduate students of Chemistry and it is based on the Chemistry syllabus of the Saurashtra University for the Inorganic Chemistry.