Substances Triple Points

Triple points for common substances. The triple point is the combination of temperature and pressure at which the three phases (gas, liquid, and solid) of a substance coexist in thermodynamic equilibrium.

Substance	Temperature (°C)	Pressure (kPa)
Acetylene	-80.7	120
Air	-213.4	5.265
Ammonia	-77.75	6.076
Argon	-189.34	68.9
Arsenic	820	3628
Butane	-138.6	0.0007
Carbon (graphite)	4492	10132
Carbon dioxide	-56.6	517
Carbon monoxide	-205.05	15.37
Chloroform	-97.72	0.87
Deuterium	-254.52	17.1
Ethane	-183.26	0.0008
Ethanol	-123	4.3e-7
Ethylene	-169.2	0.12
Formic acid	8.25	2.2
Hexafluoroethane	-100.07	26.6
Hydrogen	-259.31	7.04
Hydrogen chloride	-114.19	13.9
Iodine	113.5	12.07
Isobutane	-159.6	0.000019481
Krypton	-157.39	74.12
Mercury	-39	1.65e-7
Methane	-182.47	11.7
Neon	-248.58	43.2
Nitric oxide	-163.65	21.92
Nitrogen	-209.97	12.6
Nitrous oxide	-90.81	87.85
Oxygen	-218.79	0.152
Palladium	1552	0.0035
Platinum	1772	0.0002
Radon	-71	70
Sulfur dioxide	-75.46	1.67
Titanium	1668	0.0053
Uranium hexafluoride	64.02	151.7
Water	0.01	0.611657
Xenon	-111.8	81.5
Zinc	419.5	0.065

Calculator

Inputs

Temperature (°C)

Pressure (kPa)

Results

Temperature-- K

Temperature-- °F

Pressure-- psi

Pressure-- atm

Additional Information

Conversion Factor: 1 kPa (10³ Pa) = 0.145 psi

The triple point is not the same as the critical point. The critical point represents the temperature and pressure above which distinct gas and liquid phases do not exist, whereas the triple point is where all three phases coexist in equilibrium.