Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications!

This is an AMP page - Open full page! for all features.

Carbon Dioxide - Thermophysical Properties

Chemical, physical and thermal properties of carbon dioxide. Phase diagram included.

Sponsored Links

Carbon dioxide, CO2, is a colourless and odorless gas. It is relatively nontoxic and noncombustible, but it is heavier than air and may asphyxiate by the displacement of air. 

When CO2 is solved in water, the mild carbonic acid, is formed. Cooled CO2 in solid form is called dry ice.

Carbon dioxide phase diagram

Chemical, physical and thermal properties of carbon dioxide:
Values are given for gas phase at 25oC /77oF / 298 K and 1 atm., if not other phase, temperature or pressure given.

For full table with Imperial Units - rotate the screen!

Property Value Unit Value Unit Value Unit Value Unit
Acidity (pKa1) 6.35
Acidity (pKa2) 10.33
Boiling Point - sublimation point 194.686 K -78.464 °C -109.24 °F
Critical density 10.63 mol/dm3 467.6 kg/m3 0.9073 slug/ft3 29.19 lb/ft3
Critical pressure 7.38 MPa=MN/m2 73.8 bar 72.8 atm 1070 psi=lbf/in2
Critical temperature 304.13 K 30.98 °C 87.76 °F
Critical volume 94.12 cm3/mol 0.00214 m3/kg 1.102 ft3/slug 0.03426 ft3/lb
Density 40.8 mol/m3 1.795 kg/m3 0.00348 slug/ft3 0.1121 lb/ft3
Density, gas at 32°F/0°C 1 atm 44.9 mol/m3 1.977 kg/m3 0.00384 slug/ft3 0.1234 lb/ft3
Density, liquid at -34.6 °F/-37°C, saturation pressure 25017 mol/m3 1101 kg/m3 2.136 slug/ft3 68.73 lb/ft3
Density, solid at -109.3 °F/-78.5°C, 1 atm 35492 mol/m3 1562 kg/m3 3.031 slug/ft3 97.51 lb/ft3
Flammable no
Gas constant - R (individual) 188.92 J/kg K 0.0525 Wh/(kg K) 1130 [ft lbf/slug °R] 35.114 [ft lbf/lb °R]
Gibbs free energy of formation -394.00 kJ/mol -8953 kJ/kg -3849 Btu/lb
Heat (enthalpy) of combustion 0 kJ/mol 0 kJ/kg 0 Btu/lb
Heat (enthalpy) of formation -393.50 kJ/mol -8941 kJ/kg -3844 Btu/lb
Heat (enthalpy) of fusion 9.02 kJ/mol 205 kJ/kg 88.11 Btu/lb
Heat (enthalpy) of sublimation, at 180 K 26 kJ/mol 591 kJ/kg 254 Btu/lb
Heat (enthalpy) of vaporization at 15°C 179.5 kJ/kg 77.2 Btu/lb
Heat (enthalpy) of vaporization at triple point 15.55 kJ/mol 353.4 kJ/kg 151.93 Btu/lb
Specific heat capacity, Cp (isobaric) 37.35 J/mol K 0.849 kJ/kg K 0.203 Btu/lb°F or cal/g K
Specific heat capacity, Cv (isochoric) 28.96 J/mol K 0.658 kJ/kg K 0.157 Btu/lb°F or cal/g K
Ionization potential 13.77 eV
Molecular Weight 44.0095 g/mol 0.09702 lb/mol
pH of saturated aqueous solution 3.7
Solubility in water 0.148 g/100 g 1.48 g/l=mg/ml
Sound velocity in gas 269 m/s
Specific Gravity (density relativ to density of air) 1.53
Specific Heat Ratio - Cp/Cv 1.29
Specific Volume 0.0245 m3/mol 0.557 m3/kg 287.1 ft3/slug 8.92 ft3/lb
Standard molar entropy, S° 213.8 J/mol K 4.86 kJ/kg K 1.16 Btu/lb °F
Sublimation Point 194.686 K -78.464 °C -109.24 °F
Surface tension at melting point 16.2 dynes/cm
Thermal Conductivity 0.01663 W/m°C 0.009609 Btu/hr ft °F
Triple point pressure 0.5180 MPa=MN/m2 5.180 bar 5.112 atm 75.12 psi=lbf/in2
Triple point temperature 216.58 K -56.57 °C -69.81 °F
Vapor (saturation) pressure 6.45 MPa=MN/m2 48379 mm Hg 63.66 atm 935.5 psi=lbf/in2
Viscosity, dynamic (absolute) 1.495 cP 1004.6 [lbm/ft s*10-6] 31.22 [lbf s/ft2 *10-6]
Viscosity, kinematic 0.834 cSt 8.977 [ft2/s*10-6]

Back to top

Follow the links below to get values for the listed properties of carbon dioxide at varying pressure and temperature:

See also more about atmospheric pressure, and STP - Standard Temperature and Pressure & NTP - Normal Temperature and Pressure,
as well as Thermophysical properties of: Acetone, Acetylene, Air, Ammonia, Argon, Benzene, Butane, Carbon monoxide, Ethane, Ethanol, Ethylene, Helium, Hydrogen, Hydrogen sulfide, Methane, Methanol, Nitrogen, Oxygen, Pentane, Propane, Toluene, Water and Heavy water, D2O.

Carbon dioxide is a gas at standard conditions. However, at low temperature and/or high pressures the gas becomes a liquid or a solid.

The phase diagram for carbon dioxide shows the phase behavior with changes in temperature and pressure. The curve between the critical point and the triple point shows the carbon dioxide boiling point with changes in pressure. The curve between the triple point downwards to zero pressure shows the sublimation point with changes in pressure (Sublimation: transformation from solid phase directly to gas phase). Carbon dioxide in solid phase is called dry ice.

At the critical point there is no change of state when pressure is increased or if heat is added.

The triple point of a substance is the temperature and pressure at which the three phases (gas, liquid, and solid) of that substance coexist in thermodynamic equilibrium.

Back to top

Atmospheric CO2 Concentration

Sponsored Links

Related Topics

Related Documents

Sponsored Links


Search Engineering ToolBox

  • the most efficient way to navigate the Engineering ToolBox!

SketchUp Extension - Online 3D modeling!

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro . Add the Engineering ToolBox extension to your SketchUp from the Sketchup Extension Warehouse!


We don't collect information from our users. Only emails and answers are saved in our archive. Cookies are only used in the browser to improve user experience.

Some of our calculators and applications let you save application data to your local computer. These applications will - due to browser restrictions - send data between your browser and our server. We don't save this data.

Google use cookies for serving our ads and handling visitor statistics. Please read Google Privacy & Terms for more information about how you can control adserving and the information collected.

AddThis use cookies for handling links to social media. Please read AddThis Privacy for more information.


Unit Converters



Load Calculator!


naut miles

Load Calculator!



Load Calculator!


us gal

Load Calculator!



Load Calculator!



Load Calculator!


Pa (N/m2)
mm H2O
inches H2O

Load Calculator!


US gpm

Load Calculator!

3 30

This website use cookies. By continuing to browse you are agreeing to our use of cookies! Learn more