Major branches of inorganic chemistry include
Inorganic chemistry often overlaps with mineralogy, geochemistry,analytical chemistry, environmental chemistry, physical chemistry, and organometallic chemistry. Organometallic chemistry combines aspects of organic chemistry with inorganic chemistry, and is defined as the study of organic compounds containing metal-carbon bonds. Vitamin B12, whose active site is similar to that of hemoglobin, is a naturally-occurring, metabolically-important organometallic compound containing a large organic components (corrin and protein), a metal (cobalt), a bond between the metal and the carbon of a methyl group. Despite the presence of metal ions or metal-carbon bonds, gold cyanide, calcium carbonate, and nickel tetracarbonyl (to name just a few such) are inorganic, rather than organometallic, compounds, although some chemists consider metal carbonyls to be organometallic.
Adding to the confusion, the oxides of carbon, carbonate salts, and materials containing carbon like steel and diamond are usually considered inorganic, while the inorganic molecule nitric oxide is often studied for biochemical effects.
Much of inorganic chemistry deals with molecular compounds, i.e many inorganic materials have a structure that can be described in terms of molecules but many others do not. The study of such solids is called solid state chemistry. It is a branch of materials science.