CO2 liquid and gaseous Values
Molar mass (MCO2) 44.011 kg/kmol
Molar standard volume (Vmn) 22.263 m3/kmol
Specific gas constant (RCO2) 0.1889 kJ/(kg · K)
Standard density (ρn) 1.977 kg/m3
Density ratio CO2/air(d) 1,529
Critical temperature (Tkrit) 31 °C
Critical pressure (pkrit) 73.83 bar
Critical density (ρkrit) 466 kg/m3
Triple point (tT) -56.6 °C at 5.18 bar
Decomposition temperature approx. 1,200 °C (degree of decomposition: 0.032 % by volume)
Colour in the gaseous state colourless
Fire behaviour non-flammable, use as extinguishing agent
Combination with water CO2 + H2O dopfeil H2CO3 (approx. 0.1 % H2CO3)
Odour odourless
Flavour neutral
Toxicity Non-toxic. Authorised under food law and declaration-free
MAK value 5,000 ml/m3 (ppm) as 8-hour average value
Medical use Inhalations of 3 - 5 % CO2 in the breathing gas
Effects of different concentrations Irritation of the respiratory centre at 3 - 5 % by volume
Unconsciousness at 7 - 10 % by volume due to lack of oxygen
CO2 solid  
Sublimation point ts = -78.9 °C at 0.981 bar
Heat of sublimation rs = 573.02 kJ/kg
Cooling capacity during heating q0 ˜ 645 kJ/kg (from -78.9 °C [194.25 K] to 0 °C [273.15 K])



Water content in CO2 gas as a function of the dew point temperature


Isochores for CO2 (lines of equal density)