# Caurbon dioxide

Caurbon dioxide|  |
|

|  |  |
| --- | --- |
| Ball-an-stick model o carbon dioxide | Space-fillin model o carbon dioxide |

 |
| Names |
| Ither names
Carbonic acid gas Carbonic anhydride Carbonic oxide Carbon oxide Carbon(IV) oxide Dry ice (solid phase) |
| Identifiers |
| CAS Nummer | * 124-38-9Y
 |
| 3D model (JSmol) | * Interactive eemage
* Interactive eemage
 |
| 3DMet | B01131 |
| Beilstein Reference | 1900390 |
| ChEBI | * CHEBI:16526Y
 |
| ChEMBL | * ChEMBL1231871N
 |
| ChemSpider | * 274Y
 |
| EC Nummer | 204-696-9  |
| Gmelin Reference | 989 |
| KEGG | * D00004Y
 |
| MeSH | Carbon+dioxide |
| PubChem CID | * 280
 |
| RTECS nummer | FF6400000 |
| UNII | * 142M471B3JY
 |
| UN nummer | 1013 |
|
InChI
* InChI=1S/CO2/c2-1-3YKey: CURLTUGMZLYLDI-UHFFFAOYSA-NY
* InChI=1/CO2/c2-1-3Key: CURLTUGMZLYLDI-UHFFFAOYAO
 |
|
SMILES
* O=C=O
* C(=O)=O
 |
| Properties |
| Chemical formula | CO2 |
| Molar mass | 44.01 g·mol−1   |
| Appearance | Colorless gas |
| Odour | Odorless |
| Density | 1562 kg/m3 (solid at 1 atm an −78.5 °C) 770 kg/m3 (liquid at 56 atm an 20 °C) 1.977 kg/m3 (gas at 1 atm an 0 °C) |
| Meltin pynt |  −78.5 °C; −109.2 °F; 194.7 K  |
| Bylin pynt |  −56.6 °C; −69.8 °F; 216.6 K  |
| Solubility in watter | 1.45 g/L at 25 °C, 100 kPa |
| Vapour pressur | 5.73 MPa (20 °C) |
| Acidity (p*K*a) | 6.35, 10.33 |
| Refractive index (*n*D) | 1.1120 |
| Viscosity | 0.07 cP at −78.5 °C |
| Dipole moment | 0 D |
| Structur |
| Creestal structur | trigonal |
| Molecular shape | linear |
| Thermochemistry |
| Speceefic heat capacity, *C* | 37.135 J/K mol |
| Staundart molar entropy *S*~~o~~298 | 214 J·mol−1·K−1 |
| Std enthalpy o formation Δf*H*~~o~~298 | −393.5 kJ·mol−1 |
| Hazards |
| NFPA 704 |
0
1
0SA |
| Relatit compoonds |
| Ither anions | Caurbon disulfide Caurbon diselenide |
| Ither cations | Silicon dioxide Germanium dioxide Tin dioxide Lead dioxide |
| Except whaur itherwise notit, data are gien for materials in thair staundart state (at 25 °C [77 °F], 100 kPa). |
| Y verify (whit is YN ?) |
| Infobox references |
|  |  |

**Caurbon dioxide** (chemical formula **CO2**) is a naiturally occurrin chemical compound componed o twa oxygen atoms covalently bonded tae a single caurbon atom. It is a gas at staundart temperatur an pressur an exists in Yird's atmosphere in this state, as a trace gas at a concentration o 0.039 per cent bi volume.

As pairt o the caurbon cycle, plants, algae, an cyanobacteria uise licht energy tae photosynthesize carbohydrate frae caurbon dioxide an watter, wi oxygen produced as a waste product. Houiver, photosynthesis cannae occur in daurkness an at nicht some caurbon dioxide is produced bi plants durin respiration. Caurbon dioxide is produced bi combustion o coal or hydrocaurbons, the fermentation o succars in beer an winemakin an bi respiration o aw livin organisms. It is exhaled in the breath o humans an land ainimals. It is emittit frae volcanoes, het springs, geysers an ither places whaur the yird's crust is thin an is freed frae caurbonate rocks bi dissolution. CO2 is an aa foond in lochs, at depth unner the sea an commingled wi ile an gas deposits.

The environmental effects o caurbon dioxide are o signeeficant interest. Caurbon dioxide is an important greenhoose gas, absorbin heat radiation frae Yird's surface whilk itherwise wad hae left the atmosphere. Atmospheric caurbon dioxide is the primary soorce o caurbon in life on Yird an its concentration in Yird's pre-industrial atmosphere syne late in the Precambrian eon wis regulatit bi photosynthetic organisms. Burnin o caurbon-based fuels syne the industrial revolution haes rapidly increased concentrations o atmospheric caurbon dioxide, increasin the rate o global wairmin an causin anthropogenic climate chynge. It is an aa a major soorce o ocean acidification syne it dissolves in watter tae furm caurbonic acid, whilk is a weak acid as its ionization in watter is incomplete.

CO
2 + H
2O ⇌ H
2CO
3

## Freemit airtins

* Internaitional Chemical Safety Caird 0021
* PubChem 280
* CDC – NIOSH Pocket Guide tae Chemical Hazards – Carbon Dioxide
* CO2 Carbon Dioxide Properties, Uises, Applications
* Dry Ice information Archived 2004-04-03 at the Wayback Machine
* Trends in Atmospheric Carbon Dioxide *(NOAA)*
* "A War Gas That Saves Lives." *Popular Science*, Juin 1942, pp. 53–57.
* NASA's Orbitin Carbon Observatory Archived 2018-09-09 at the Wayback Machine
* The on-line catalogue of CO2 naitural emissions in Italy Archived 2021-02-13 at the Wayback Machine
* Reactions, Thermochemistry, Uises, an Function o Carbon Dioxide Archived 2021-02-13 at the Wayback Machine
* Carbon Dioxide – Pairt Ane an Carbon Dioxide – Pairt Twa at *The Periodic Table o Videos* (Varsity o Nottingham)