This book contains eight chapters that detail the chemistry of several elements. Chapter One provides an overview of in vitro antiproliferative and cytotoxic activity of novel Ru (II)-polypyridine complexes on SK-MEL-28 and normal L6 cell lines. Chapter Two discusses the successful development of organometallic complexes as potential anticancer drugs in light of their adaptable structural chemistry and creative modes of action that target nucleic acids and other enzymes. Chapter Three details the design, structural Diversity,and luminescence properties of gadolinium-based solid state phosphors. Chapter Four considers the main homogeneous and heterogeneous catalysts based on ruthenium that are used for the hydrogenation of dienes and compounds with a conjugated diene system. Chapter Five elaborates on the magneto-optical effects of rubidium atoms obtained by applying magnetic and optical fields. Chapter Six presents the biogeochemistry of rubidium. Chapter Seven assesses the ecological state of brown forest acidic soil when contaminated with chemical compounds of tellurium. Finally, Chapter Eight discusses the function of ruthenium complexes in neurological disorders.