Caurbon dioxide

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.^[1]

Caurbon dioxide

Names
Ither names Carbonic acid gas Carbonic anhydride Carbonic oxide Carbon oxide Carbon(IV) oxide Dry ice (solid phase)
Identifiers
CAS Nummer	124-38-9 Y
3D model (JSmol)	Interactive eemage Interactive eemage
3DMet	B01131
Beilstein Reference	1900390
ChEBI	CHEBI:16526 Y
ChEMBL	ChEMBL1231871 N
ChemSpider	274 Y
EC Nummer	204-696-9
Gmelin Reference	989
KEGG	D00004 Y
MeSH	Carbon+dioxide
PubChem CID	280
RTECS nummer	FF6400000
UNII	142M471B3J Y
UN nummer	1013
InChI InChI=1S/CO2/c2-1-3 Y Key: CURLTUGMZLYLDI-UHFFFAOYSA-N Y InChI=1/CO2/c2-1-3 Key: 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 (pKa)	6.35, 10.33
Refractive index (nD)	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 So298	214 J·mol−1·K−1
Std enthalpy o formation ΔfHo298	−393.5 kJ·mol−1
Hazards
NFPA 704	0 1 0 SA
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

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.^[2] Houiver, photosynthesis cannae occur in daurkness an at nicht some caurbon dioxide is produced bi plants durin respiration.^[3] 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.^[4]

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,^[5] whilk is a weak acid as its ionization in watter is incomplete.

CO
₂ + H
₂O ⇌ H
₂CO
₃