Inorganic compound

Inorganic compounds have traditionally been considered to be of inanimate, non-biological origin. And most organic compounds have been viewed as being of biological origin. However, over the past century, the classification of inorganic vs organic compounds has become less important to scientists, primarily because the majority of known compounds are synthetic and not of natural origin. Furthermore, most compounds considered the purview of modern inorganic chemistry contain organic ligands and many materials that are found in living organisms contain heavy atoms. The fields of organometallic chemistry and bioinorganic chemistry explicitly focus on the areas between the fields of organic, biological, and inorganic chemistry. Many minerals, ostensibly inorganic, are the products of biological processes. IUPAC, an agency widely recognized for defining chemical terms, does not offer definitions of inorganic or organic.

Modern usage
Inorganic compounds can be formally defined with reference to what they are not — organic compounds. Organic compounds contain carbon bonds in which at least one carbon atom is covalently linked to an atom of another type (commonly hydrogen, oxygen, or nitrogen). Some carbon-containing compounds are traditionally considered inorganic. When considering inorganic chemistry and life, it is useful to recall that many species in nature are not compounds per se but are ions (e.g., proteins, DNA, and RNA). Sodium, chloride, and phosphate ions are essential for life, as are some inorganic molecules such as carbonic acid, nitrogen, carbon dioxide, water, and oxygen. Aside from these simple ions and molecules, virtually all compounds covered by bioinorganic chemistry contain carbon and can be considered organic or organometallic.

Inorganic carbon compounds
Many compounds that contain carbon are considered inorganic, for example, carbon monoxide, carbon dioxide, carbonates, cyanides, cyanates, carbides, and thyocyanates. In general, however, the workers in these areas are not concerned about strict definitions.

Coordination chemistry
A large class of compounds discussed in inorganic chemistry textbooks are coordination compounds. Examples range from substances that are strictly inorganic, such as [Co(NH3)6]Cl3, to organometallic compounds, such as Fe(C5H5)2, and extending to bioinorganic compounds, such as the hydrogenase enzymes.

Mineralogy
Minerals are mainly oxides and sulfides, which are strictly inorganic, although they may be of biological origin. In fact, most of the earth - and the rest of the universe - is inorganic. Although the components of Earth's crust are well-elucidated, the processes of mineralization and the composition of the deep mantle remain active areas of investigation, which are covered mainly in geology-oriented venues.