An inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. However, the distinction is not clearly defined and agreed upon, and authorities have differing views on the subject.
Inorganic compounds comprise most of the Earth's crust, although the compositions of the deep mantle remain active areas of investigation.
Some simple compounds that contain carbon are often considered inorganic. Examples include carbon monoxide, carbon dioxide, carbonates, carbides, cyanides, cyanates, and thiocyanates. Many of these are normal parts of mostly organic systems, including organisms; describing a chemical as inorganic does not necessarily mean that it does not occur within living things.
Friedrich Wöhler's conversion of ammonium cyanate into urea in 1828 is often cited as the starting point of modern organic chemistry. In Wöhler era, there was widespread belief that organic compounds were characterized by a vital spirit. In the absence of vitalism, the distinction between inorganic and organic chemistry is merely semantic.
- The Inorganic Crystal Structure Database (ICSD) in its definition of "inorganic" carbon compounds, states that such compounds may contain either C-H or C-C bonds, but not both.
- The book series Inorganic Syntheses does not define inorganic compounds. The majority of its content deals with metal complexes of organic ligands.
- IUPAC does not offer a definition of "inorganic" or "inorganic compound" but does define inorganic polymer as "...skeletal structure that does not include carbon atoms."
- Some major textbooks on inorganic chemistry decline to define inorganic compounds: Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Francisco, 2001. ISBN 0-12-352651-5; Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8., Cotton, F. Albert; Wilkinson, Geoffrey (1988), Advanced Inorganic Chemistry (5th ed.), New York: Wiley-Interscience, ISBN 0-471-84997-9
- J. J. Berzelius "Lehrbuch der Chemie," 1st ed., Arnoldischen Buchhandlung, Dresden and Leipzig, 1827. ISBN 1-148-99953-1. Brief English commentary in English can be found in Bent Soren Jorgensen "More on Berzelius and the vital force" J. Chem. Educ., 1965, vol. 42, p 394. doi:10.1021/ed042p394
- Dan Berger, Bluffton College, analysis of varying inappropriate definitions of the inorganic-organic distinction: Otherwise consistent linked material differing from current article in downplaying the carbon present vs carbon absent distinctive:
- Newman, D. K.; Banfield, J. F. (2002). "Geomicrobiology: How Molecular-Scale Interactions Underpin Biogeochemical Systems". Science. 296 (5570): 1071–1077. doi:10.1126/science.1010716. PMID 12004119.
- May, Paul. "Urea". Molecules in Motion. Imperial College London. Archived from the original on 2015-03-17.
- Cohen, Paul S.; Cohen, Stephen M. (1996). "Wöhler's Synthesis of Urea: How do the Textbooks Report It?". Journal of Chemical Education. 73: 883. doi:10.1021/ed073p883.
- Ramberg, Peter J. (2000). "The Death of Vitalism and the Birth of Organic Chemistry: Wohler's Urea Synthesis and the Disciplinary Identity of Organic Chemistry". Ambix. 47 (3): 170–195. doi:10.1179/amb.2000.47.3.170. PMID 11640223.
- "Inorganic Crystal Structure Database" (PDF). Archived from the original (PDF) on 2017-08-30. Retrieved 2017-01-13.
- "Volumes - Inorganic Syntheses". www.inorgsynth.org.
- IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "inorganic polymer". doi:10.1351/goldbook.IT07515