Global InformationCarbon dioxide information
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| Names | |||
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| IUPAC name
Carbon dioxide
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Other names
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| Identifiers | |||
CAS Number
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3D model (JSmol)
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| 3DMet |
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Beilstein Reference
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1900390 | ||
| ChEBI |
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| ChEMBL |
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| ChemSpider |
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| ECHA InfoCard | 100.004.271 | ||
| EC Number |
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| E number | E290 (preservatives) | ||
Gmelin Reference
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989 | ||
| KEGG |
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| MeSH | Carbon+dioxide | ||
PubChem CID
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| RTECS number |
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| UNII |
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| UN number | 1013 (gas), 1845 (solid) | ||
CompTox Dashboard (EPA)
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InChI
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SMILES
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| Properties | |||
Chemical formula
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CO2 | ||
| Molar mass | 44.009 g·mol−1 | ||
| Appearance | Colorless gas | ||
| Odor |
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| Density |
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| Critical point (T, P) | 304.128(15) K[2] (30.978(15) °C), 7.3773(30) MPa[2] (72.808(30) atm) | ||
Sublimation
conditions |
194.6855(30) K (−78.4645(30) °C) at 1 atm (0.101325 MPa) | ||
Solubility in water
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1.45 g/L at 25 °C (77 °F), 100 kPa (0.99 atm) | ||
| Vapor pressure | 5.7292(30) MPa, 56.54(30) atm (20 °C (293.15 K)) | ||
| Acidity (pKa) | Carbonic acid: pKa1 = 3.6 pKa1(apparent) = 6.35 pKa2 = 10.33 | ||
Magnetic susceptibility (χ)
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−20.5·10−6 cm3/mol | ||
| Thermal conductivity | 0.01662 W·m−1·K−1 (300 K (27 °C; 80 °F))[3] | ||
Refractive index (nD)
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1.00045 | ||
| Viscosity |
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Dipole moment
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0 D | ||
| Structure | |||
Crystal structure
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Trigonal | ||
Molecular shape
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Linear | ||
| Thermochemistry | |||
Heat capacity (C)
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37.135 J/(K·mol) | ||
Std molar
entropy (S⦵298) |
214 J·mol−1·K−1 | ||
Std enthalpy of
formation (ΔfH⦵298) |
−393.5 kJ·mol−1 | ||
| Pharmacology | |||
ATC code
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V03AN02 (WHO) | ||
| Hazards | |||
| NFPA 704 (fire diamond) | [7][8] 
2
0
0 SA | ||
| Lethal dose or concentration (LD, LC): | |||
LCLo (lowest published)
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90,000 ppm (162,000 mg/m3) (human, 5 min)[6] | ||
| NIOSH (US health exposure limits): | |||
PEL (Permissible)
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TWA 5000 ppm (9000 mg/m3)[5] | ||
REL (Recommended)
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TWA 5000 ppm (9000 mg/m3), ST 30,000 ppm (54,000 mg/m3)[5] | ||
IDLH (Immediate danger)
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40,000 ppm (72,000 mg/m3)[5] | ||
| Safety data sheet (SDS) | Sigma-Aldrich | ||
| Related compounds | |||
Other anions
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Other cations
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Related carbon oxides
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See Oxocarbon | ||
Related compounds
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| Supplementary data page | |||
| Carbon dioxide (data page) | |||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
 verify (what is   ?)
Infobox references
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Carbon dioxide is a chemical compound with the chemical formula CO2. It is made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature, and as the source of available carbon in the carbon cycle, atmospheric CO2 is the primary carbon source for life on Earth. In the air, carbon dioxide is transparent to visible light but absorbs infrared radiation, acting as a greenhouse gas. Carbon dioxide is soluble in water and is found in groundwater, lakes, ice caps, and seawater. When carbon dioxide dissolves in water, it forms carbonate and mainly bicarbonate (HCO−3), which causes ocean acidification as atmospheric CO2 levels increase.[9]
It is a trace gas in Earth's atmosphere at 421 parts per million (ppm)[a], or about 0.04% (as of May 2022) having risen from pre-industrial levels of 280 ppm or about 0.025%.[11][12] Burning fossil fuels is the primary cause of these increased CO2 concentrations and also the primary cause of climate change.[13]
Its concentration in Earth's pre-industrial atmosphere since late in the Precambrian was regulated by organisms and geological phenomena. Plants, algae and cyanobacteria use energy from sunlight to synthesize carbohydrates from carbon dioxide and water in a process called photosynthesis, which produces oxygen as a waste product.[14] In turn, oxygen is consumed and CO2 is released as waste by all aerobic organisms when they metabolize organic compounds to produce energy by respiration.[15] CO2 is released from organic materials when they decay or combust, such as in forest fires. Since plants require CO2 for photosynthesis, and humans and animals depend on plants for food, CO2 is necessary for the survival of life on earth.
Carbon dioxide is 53% more dense than dry air, but is long lived and thoroughly mixes in the atmosphere. About half of excess CO2 emissions to the atmosphere are absorbed by land and ocean carbon sinks.[16] These sinks can become saturated and are volatile, as decay and wildfires result in the CO2 being released back into the atmosphere.[17] CO2 is eventually sequestered (stored for the long term) in rocks and organic deposits like coal, petroleum and natural gas. Sequestered CO2 is released into the atmosphere through burning fossil fuels or naturally by volcanoes, hot springs, geysers, and when carbonate rocks dissolve in water or react with acids.
CO2 is a versatile industrial material, used, for example, as an inert gas in welding and fire extinguishers, as a pressurizing gas in air guns and oil recovery, and as a supercritical fluid solvent in decaffeination and supercritical drying.[18] It is a byproduct of fermentation of sugars in bread, beer and wine making, and is added to carbonated beverages like seltzer and beer for effervescence. It has a sharp and acidic odor and generates the taste of soda water in the mouth, but at normally encountered concentrations it is odorless.[1]
- ^ a b Cite error: The named reference
AirProductsMSDSwas invoked but never defined (see the help page). - ^ a b Span R, Wagner W (1 November 1996). "A New Equation of State for Carbon Dioxide Covering the Fluid Region from the Triple-Point Temperature to 1100 K at Pressures up to 800 MPa". Journal of Physical and Chemical Reference Data. 25 (6): 1519. Bibcode:1996JPCRD..25.1509S. doi:10.1063/1.555991.
- ^ Touloukian YS, Liley PE, Saxena SC (1970). "Thermophysical properties of matter - the TPRC data series". Thermal Conductivity - Nonmetallic Liquids and Gases. 3. Data book.
- ^ Schäfer M, Richter M, Span R (2015). "Measurements of the viscosity of carbon dioxide at temperatures from (253.15 to 473.15) K with pressures up to 1.2 MPa". The Journal of Chemical Thermodynamics. 89: 7–15. doi:10.1016/j.jct.2015.04.015.
- ^ a b c NIOSH Pocket Guide to Chemical Hazards. "#0103". National Institute for Occupational Safety and Health (NIOSH).
- ^ "Carbon dioxide". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
- ^ "Safety Data Sheet – Carbon Dioxide Gas – version 0.03 11/11" (PDF). AirGas.com. 12 February 2018. Archived (PDF) from the original on 4 August 2018. Retrieved 4 August 2018.
- ^ "Carbon dioxide, refrigerated liquid" (PDF). Praxair. p. 9. Archived from the original (PDF) on 29 July 2018. Retrieved 26 July 2018.
- ^ Ocean Acidification: A National Strategy to Meet the Challenges of a Changing Ocean. Washington, DC: National Academies Press. 22 April 2010. pp. 23–24. doi:10.17226/12904. ISBN 978-0-309-15359-1. Archived from the original on 5 February 2016. Retrieved 29 February 2016.
- ^ "CO2 Gas Concentration Defined". CO2 Meter. 18 November 2022. Retrieved 5 September 2023.
- ^ Eggleton T (2013). A Short Introduction to Climate Change. Cambridge University Press. p. 52. ISBN 9781107618763. Retrieved 9 November 2020.
- ^ "Carbon dioxide now more than 50% higher than pre-industrial levels | National Oceanic and Atmospheric Administration". www.noaa.gov. 3 June 2022. Retrieved 14 June 2022.
- ^ IPCC (2022) Summary for policy makers in Climate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, United Kingdom and New York, NY, US
- ^ Kaufman DG, Franz CM (1996). Biosphere 2000: protecting our global environment. Kendall/Hunt Pub. Co. ISBN 978-0-7872-0460-0.
- ^ "Food Factories". www.legacyproject.org. Archived from the original on 12 August 2017. Retrieved 10 October 2011.
- ^ IPCC (2021). "Summary for Policymakers" (PDF). Climate Change 2021: The Physical Science Basis. p. 20. Archived (PDF) from the original on 10 October 2022.
- ^ Myles, Allen (September 2020). "The Oxford Principles for Net Zero Aligned Carbon Offsetting" (PDF). Archived (PDF) from the original on 2 October 2020. Retrieved 10 December 2021.
- ^ Tsotsas E, Mujumdar AS (2011). Modern drying technology. Vol. 3: Product quality and formulation. John Wiley & Sons. ISBN 978-3-527-31558-1. Archived from the original on 21 March 2020. Retrieved 3 December 2019.
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