- Formula: C2H2
- Molecular weight: 26.0373
- IUPAC Standard InChI:
- Download the identifier in a file.
- IUPAC Standard InChIKey: HSFWRNGVRCDJHI-UHFFFAOYSA-N
- CAS Registry Number: 74-86-2
- Chemical structure:
This structure is also available as a 2d Mol file or as a computed 3d SD file
- Other names: Ethyne; Ethine; Narcylen; C2H2; Acetylen; UN 1001; Vinylene
- Permanent link for this species. Use this link for bookmarking this species for future reference.
- Information on this page:
- Other data available:
- Data at other public NIST sites:
Data at NIST subscription sites:
- NIST / TRC Web Thermo Tables, "lite" edition (thermophysical and thermochemical data)
- NIST / TRC Web Thermo Tables, professional edition (thermophysical and thermochemical data)
NIST subscription sites provide data under the NIST Standard Reference Data Program, but require an annual fee to access. The purpose of the fee is to recover costs associated with the development of data collections included in such sites. Your institution may already be a subscriber. Follow the links above to find out more about the data in these sites and their terms of usage.
Gas phase thermochemistry data
Go To: Top, References, Notes
Data compiled as indicated in comments:
DRB - Donald R. Burgess, Jr.
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
GT - Glushko Thermocenter, Russian Academy of Sciences, Moscow
|fH°gas||226.73||kJ/mol||Review||Chase, 1998||Data last reviewed in March, 1961|
|fH°gas||227.4 ± 0.8||kJ/mol||Review||Manion, 2002||adopted recommendation of Gurvich, Veyts, et al., 1991; DRB|
|fH°gas||226.7 ± 0.79||kJ/mol||Ccb||Wagman, Kilpatrick, et al., 1945||Unpublished work of E. J. Prosen; ALS|
|S°gas,1 bar||200.93||J/mol*K||Review||Chase, 1998||Data last reviewed in March, 1961|
Constant pressure heat capacity of gas
|Cp,gas (J/mol*K)||Temperature (K)||Reference||Comment|
|29.35||100.||Gurvich, Veyts, et al., 1989||p=1 bar.; GT|
Gas Phase Heat Capacity (Shomate Equation)
Cp° = A + B*t + C*t2 + D*t3 +
H° − H°298.15= A*t + B*t2/2 + C*t3/3 + D*t4/4 − E/t + F − H
S° = A*ln(t) + B*t + C*t2/2 + D*t3/3 − E/(2*t2) + G
Cp = heat capacity (J/mol*K)
H° = standard enthalpy (kJ/mol)
S° = standard entropy (J/mol*K)
t = temperature (K) / 1000.
|Temperature (K)||298. - 1100.||1100. - 6000.|
|Reference||Chase, 1998||Chase, 1998|
|Comment||Data last reviewed in March, 1961||Data last reviewed in March, 1961|
Go To: Top, Gas phase thermochemistry data, Notes
Chase, M.W., Jr., NIST-JANAF Themochemical Tables, Fourth Edition, J. Phys. Chem. Ref. Data, Monograph 9, 1998, 1-1951. [all data]
Manion, J.A., Evaluated Enthalpies of Formation of the Stable Closed Shell C1 and C2 Chlorinated Hydrocarbons, J. Phys. Chem. Ref. Data, 2002, 31, 1, 123-172, https://doi.org/10.1063/1.1420703 . [all data]
Gurvich, Veyts, et al., 1991
Thermodynamic Properties of Individual Substances, 4th edition, Volume 2, Gurvich, L.V.; Veyts, I.V.; Alcock, C.B.;, ed(s)., Hemisphere, New York, 1991. [all data]
Wagman, Kilpatrick, et al., 1945
Wagman, D.D.; Kilpatrick, J.E.; Pitzer, K.S.; Rossini, F.D., Heats, equilibrium constants, and free energies of formation of the acetylene hydrocarbons through the pentynes, to 1,500° K, J. Res. NBS, 1945, 35, 467-496. [all data]
Gurvich, Veyts, et al., 1989
Gurvich, L.V.; Veyts, I.V.; Alcock, C.B., Thermodynamic Properties of Individual Substances, 4th ed.; Vols. 1 and 2, Hemisphere, New York, 1989. [all data]
Go To: Top, Gas phase thermochemistry data, References
- Symbols used in this document:
Cp,gas Constant pressure heat capacity of gas S°gas,1 bar Entropy of gas at standard conditions (1 bar) fH°gas Enthalpy of formation of gas at standard conditions
- Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
- The National Institute of Standards and Technology (NIST) uses its best efforts to deliver a high quality copy of the Database and to verify that the data contained therein have been selected on the basis of sound scientific judgment. However, NIST makes no warranties to that effect, and NIST shall not be liable for any damage that may result from errors or omissions in the Database.
- Customer support for NIST Standard Reference Data products.