Inorganic compound

Main article: Inorganic chemistry

Inorganic compounds are of inanimate, not biological origin. Inorganic compounds lack carbon and hydrogen atoms and are synthesized by the agency of geological systems. In contrast, the synthesis of organic compounds in biological systems incorporates carbohydrates into the molecular structure. Organic chemists traditionally refer to any molecule containing carbon as an organic compound and by default this means that inorganic chemistry deals with molecules lacking carbon. However, biologists may distinguish organic from inorganic compounds in a different way that does not hinge on the presence of a carbon atom. Pools of organic matter, for example, that have been metabolically incorporated into living tissues persist in decomposing tissues, but as molecules become oxidized into the open environment, such as atmospheric CO₂, this creates a separate pool of inorganic compounds. The distinction between inorganic and organic compounds is not always clear when dealing with open and closed systems, because everything is ultimately connected to everything else on the planet. Some scientists, for example, view the open environment (i.e., the ecosphere) as an extension of life and from this perspective may consider atmospheric CO₂ as an organic compound. IUPAC, an agency widely recognized for defining chemical terms, does not offer definitions of inorganic or organic. Hence, the definition for an inorganic versus an organic compound in a multidisciplinary context spans the division between living (or animate) and non-living (or inanimate) matter and remains open to debate according to the way that one views the world.

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.

See also

• List of inorganic compounds
• Named inorganic compounds
• Inorganic compounds by element
• Organic compound

External links

• What is the difference between an inorganic and organic compound? MadSci Network: Chemistry, Nov. 30, 2000