A chemical compound is a substance formed when two or more elements are chemically bonded together in a fixed ratio. These bonds result in a new material whose properties are distinct from the individual elements that comprise it. The stability and structure of a compound are determined by the nature of the bonds—which can involve covalent, ionic, or metallic sharing or transfer of electrons. Analysis of these compounds requires understanding stoichiometry and molecular geometry, and determination of their precise composition can be achieved through various physical measurements such as mass spectrometry and spectroscopy.