Acetylene

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Gas phase thermochemistry data

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

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

Quantity Value Units Method Reference Comment
Δfgas54.190kcal/molReviewChase, 1998Data last reviewed in March, 1961
Δfgas54.3 ± 0.2kcal/molReviewManion, 2002adopted recommendation of Gurvich, Veyts, et al., 1991; DRB
Δfgas54.19 ± 0.19kcal/molCcbWagman, Kilpatrick, et al., 1945Unpublished work of E. J. Prosen; ALS
Quantity Value Units Method Reference Comment
gas,1 bar48.023cal/mol*KReviewChase, 1998Data last reviewed in March, 1961

Constant pressure heat capacity of gas

Cp,gas (cal/mol*K) Temperature (K) Reference Comment
7.015100.Gurvich, Veyts, et al., 1989p=1 bar.; GT
8.501200.
10.53298.15
10.56300.
12.04400.
13.09500.
13.89600.
14.57700.
15.18800.
15.73900.
16.241000.
16.711100.
17.131200.
17.521300.
17.871400.
18.181500.
18.471600.
18.731700.
18.961800.
19.171900.
19.362000.
19.542100.
19.702200.
19.842300.
19.982400.
20.112500.
20.222600.
20.332700.
20.432800.
20.532900.
20.623000.

Gas Phase Heat Capacity (Shomate Equation)

Cp° = A + B*t + C*t2 + D*t3 + E/t2
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 (cal/mol*K)
    H° = standard enthalpy (kcal/mol)
    S° = standard entropy (cal/mol*K)
    t = temperature (K) / 1000.

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Temperature (K) 298. to 1100.1100. to 6000.
A 9.72442016.12630
B 9.7353712.808581
C -3.866731-0.483143
D 0.8770890.032551
E -0.157364-2.343790
F 50.3601144.32481
G 56.1675960.59601
H 54.1901154.19011
ReferenceChase, 1998Chase, 1998
Comment Data last reviewed in March, 1961 Data last reviewed in March, 1961

Reaction thermochemistry data

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled as indicated in comments:
B - John E. Bartmess
M - Michael M. Meot-Ner (Mautner) and Sharon G. Lias
RCD - Robert C. Dunbar
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
MS - José A. Martinho Simões

Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. A general reaction search form is also available. Future versions of this site may rely on reaction search pages in place of the enumerated reaction displays seen below.

Individual Reactions

C2H- + Hydrogen cation = Acetylene

By formula: C2H- + H+ = C2H2

Quantity Value Units Method Reference Comment
Δr379. ± 5.kcal/molAVGN/AAverage of 8 values; Individual data points
Quantity Value Units Method Reference Comment
Δr370. ± 5.kcal/molAVGN/AAverage of 7 values; Individual data points

COS+ + Acetylene = (COS+ • Acetylene)

By formula: COS+ + C2H2 = (COS+ • C2H2)

Quantity Value Units Method Reference Comment
Δr27.7kcal/molPD/KERDGraul S.T. and Bowers, 1991gas phase; ΔrH>=; M
Δr34.kcal/molPDissOrlando, Friedman, et al., 1990gas phase; M
Δr34.kcal/molPDissOrlando, Friedman, et al., 1990gas phase; M
Δr33.7 ± 5.3kcal/molPDissOrlando, Friedman, et al., 1990gas phase; ΔrH<; M

Cobalt ion (1+) + Acetylene = (Cobalt ion (1+) • Acetylene)

By formula: Co+ + C2H2 = (Co+ • C2H2)

Quantity Value Units Method Reference Comment
Δr43.0 ± 1.9kcal/molIRMPDSurya, Ranatunga, et al., 1997RCD

Enthalpy of reaction

ΔrH° (kcal/mol) T (K) Method Reference Comment
6.5 (+3.1,-0.) CIDArmentrout and Kickel, 1994gas phase; ΔrH >=, guided ion beam CID; M

Nickel ion (1+) + Acetylene = (Nickel ion (1+) • Acetylene)

By formula: Ni+ + C2H2 = (Ni+ • C2H2)

Quantity Value Units Method Reference Comment
Δr44.9 ± 1.9kcal/molIRMPDSurya, Ranatunga, et al., 1997RCD

Enthalpy of reaction

ΔrH° (kcal/mol) T (K) Method Reference Comment
1.7 (+4.3,-0.) CIDArmentrout and Kickel, 1994gas phase; ΔrH>=, guided ion beam CID; M

2Hydrogen + Acetylene = Ethane

By formula: 2H2 + C2H2 = C2H6

Quantity Value Units Method Reference Comment
Δr-74.58 ± 0.15kcal/molChydConn, Kistiakowsky, et al., 1939gas phase; Reanalyzed by Cox and Pilcher, 1970, Original value = -75.06 ± 0.66 kcal/mol; At 355 K; ALS

2,5-Norbornadiene = 1,3-Cyclopentadiene + Acetylene

By formula: C7H8 = C5H6 + C2H2

Quantity Value Units Method Reference Comment
Δr28.00 ± 0.50kcal/molKinWalsh and Wells, 1975gas phase; Reanalyzed by Pedley, Naylor, et al., 1986, Original value = 28.36 ± 0.32 kcal/mol; ALS

C2Na2 (cr) + 2Water (l) = 2(Sodium hydroxide • 1418Water) (solution) + Acetylene (g)

By formula: C2Na2 (cr) + 2H2O (l) = 2(HNaO • 1418H2O) (solution) + C2H2 (g)

Quantity Value Units Method Reference Comment
Δr-38.67 ± 0.36kcal/molRSCJohnson, van Deventer, et al., 1973Please also see Pedley and Rylance, 1977.; MS

C2HCs (cr) + Water (l) = (Cesium hydroxide • 1031Water) (solution) + Acetylene (g)

By formula: C2HCs (cr) + H2O (l) = (HCsO • 1031H2O) (solution) + C2H2 (g)

Quantity Value Units Method Reference Comment
Δr-12.9 ± 0.2kcal/molRSCAder and Hubbard, 1973Please also see Pedley and Rylance, 1977.; MS

C2HNa (cr) + Water (l) = (Sodium hydroxide • 1418Water) (solution) + Acetylene (g)

By formula: C2HNa (cr) + H2O (l) = (HNaO • 1418H2O) (solution) + C2H2 (g)

Quantity Value Units Method Reference Comment
Δr-13.0 ± 0.2kcal/molRSCJohnson, van Deventer, et al., 1973Please also see Pedley and Rylance, 1977.; MS

Copper ion (1+) + Acetylene = (Copper ion (1+) • Acetylene)

By formula: Cu+ + C2H2 = (Cu+ • C2H2)

Enthalpy of reaction

ΔrH° (kcal/mol) T (K) Method Reference Comment
2.4 (+2.4,-0.) CIDArmentrout and Kickel, 1994gas phase; ΔrH>=, guided ion beam CID; M

2Acetylene = 1-Buten-3-yne

By formula: 2C2H2 = C4H4

Quantity Value Units Method Reference Comment
Δr55.8kcal/molCmReppe, Schlichting, et al., 1948liquid phase; ALS
Δr49.6kcal/molCmReppe, Schlichting, et al., 1948gas phase; ALS

Rh+ + Acetylene = (Rh+ • Acetylene)

By formula: Rh+ + C2H2 = (Rh+ • C2H2)

Enthalpy of reaction

ΔrH° (kcal/mol) T (K) Method Reference Comment
30.9 CIDChen and Armetrout, 1995gas phase; ΔrH>=, guided ion beam CID; M

Chromium ion (1+) + Acetylene = (Chromium ion (1+) • Acetylene)

By formula: Cr+ + C2H2 = (Cr+ • C2H2)

Enthalpy of reaction

ΔrH° (kcal/mol) T (K) Method Reference Comment
44.0 (+4.8,-0.) CIDArmentrout and Kickel, 1994gas phase; guided ion beam CID; M

Titanium ion (1+) + Acetylene = (Titanium ion (1+) • Acetylene)

By formula: Ti+ + C2H2 = (Ti+ • C2H2)

Enthalpy of reaction

ΔrH° (kcal/mol) T (K) Method Reference Comment
60.5 (+4.8,-0.) CIDArmentrout and Kickel, 1994gas phase; guided ion beam CID; M

Lanthanum ion (1+) + Acetylene = (Lanthanum ion (1+) • Acetylene)

By formula: La+ + C2H2 = (La+ • C2H2)

Enthalpy of reaction

ΔrH° (kcal/mol) T (K) Method Reference Comment
62.6 (+7.2,-0.) CIDArmentrout and Kickel, 1994gas phase; guided ion beam CID; M

Scandium ion (1+) + Acetylene = (Scandium ion (1+) • Acetylene)

By formula: Sc+ + C2H2 = (Sc+ • C2H2)

Enthalpy of reaction

ΔrH° (kcal/mol) T (K) Method Reference Comment
57.4 (+4.8,-0.) CIDArmentrout and Kickel, 1994gas phase; guided ion beam CID; M

Vanadium ion (1+) + Acetylene = (Vanadium ion (1+) • Acetylene)

By formula: V+ + C2H2 = (V+ • C2H2)

Enthalpy of reaction

ΔrH° (kcal/mol) T (K) Method Reference Comment
49.0 (+4.8,-0.) CIDArmentrout and Kickel, 1994gas phase; guided ion beam CID; M

Yttrium ion (1+) + Acetylene = (Yttrium ion (1+) • Acetylene)

By formula: Y+ + C2H2 = (Y+ • C2H2)

Enthalpy of reaction

ΔrH° (kcal/mol) T (K) Method Reference Comment
60.5 (+7.2,-0.) CIDArmentrout and Kickel, 1994gas phase; guided ion beam CID; M

Bromine anion + Acetylene = C2H2Br-

By formula: Br- + C2H2 = C2H2Br-

Quantity Value Units Method Reference Comment
Δr8.60kcal/molLPESWild, Milley, et al., 2000gas phase; Given: 8.635±0.009 kcal/mol(0 K); B

C2Ag2 (cr) + 2(Hydrogen chloride • 12.3Water) (solution) = Acetylene (aq) + 2Silver chloride (cr)

By formula: C2Ag2 (cr) + 2(HCl • 12.3H2O) (solution) = C2H2 (aq) + 2AgCl (cr)

Quantity Value Units Method Reference Comment
Δr-18.6 ± 0.1kcal/molRSCFinch, Gardner, et al., 1991MS

(CAS Reg. No. 25012-81-1 • 4294967295Acetylene) + Acetylene = CAS Reg. No. 25012-81-1

By formula: (CAS Reg. No. 25012-81-1 • 4294967295C2H2) + C2H2 = CAS Reg. No. 25012-81-1

Quantity Value Units Method Reference Comment
Δr33.02 ± 0.72kcal/molN/AErvin, Gronert, et al., 1990gas phase; B

Aluminum ion (1+) + Acetylene = (Aluminum ion (1+) • Acetylene)

By formula: Al+ + C2H2 = (Al+ • C2H2)

Quantity Value Units Method Reference Comment
Δr13.0 ± 2.0kcal/molCIDC,EqGStockigt, Schwarz, et al., 1996Anchored to theory; RCD

Ethylene, 1,2-dichloro-, (Z)- = Acetylene + Chlorine

By formula: C2H2Cl2 = C2H2 + Cl2

Quantity Value Units Method Reference Comment
Δr5.1kcal/molKinLaursen and Pimentel, 1989gas phase; Photolyses; ALS

Ethene, chloro- = Acetylene + Hydrogen chloride

By formula: C2H3Cl = C2H2 + HCl

Quantity Value Units Method Reference Comment
Δr24.06 ± 0.28kcal/molCmLacher, Gottlieb, et al., 1962gas phase; ALS

1,3-Cyclopentadiene + Acetylene = 2,5-Norbornadiene

By formula: C5H6 + C2H2 = C7H8

Quantity Value Units Method Reference Comment
Δr-28.0 ± 0.5kcal/molEqkWalsh and Wells, 1975gas phase; ALS

C2H2+ + Acetylene = (C2H2+ • Acetylene)

By formula: C2H2+ + C2H2 = (C2H2+ • C2H2)

Quantity Value Units Method Reference Comment
Δr22.6kcal/molPIOno and Ng, 1982gas phase; M

Iron ion (1+) + Acetylene = (Iron ion (1+) • Acetylene)

By formula: Fe+ + C2H2 = (Fe+ • C2H2)

Quantity Value Units Method Reference Comment
Δr36.1 ± 1.9kcal/molIRMPDSurya, Ranatunga, et al., 1997RCD

(Z)-1,2-Diiodoethylene = Acetylene + Iodine

By formula: C2H2I2 = C2H2 + I2

Quantity Value Units Method Reference Comment
Δr19.9kcal/molEqkFuruyama, Golden, et al., 1968gas phase; ALS

C2H2I2 = Acetylene + Iodine

By formula: C2H2I2 = C2H2 + I2

Quantity Value Units Method Reference Comment
Δr19.9kcal/molEqkFuruyama, Golden, et al., 1968gas phase; ALS

Henry's Law data

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled by: Rolf Sander

Henry's Law constant (water solution)

kH(T) = H exp(d(ln(kH))/d(1/T) ((1/T) - 1/(298.15 K)))
H = Henry's law constant for solubility in water at 298.15 K (mol/(kg*bar))
d(ln(kH))/d(1/T) = Temperature dependence constant (K)

H (mol/(kg*bar)) d(ln(kH))/d(1/T) (K) Method Reference Comment
0.039 QN/A missing citation give several references for the Henry's law constants but don't assign them to specific species.
0.0411800.LN/A 
0.042 VN/A 

Vibrational and/or electronic energy levels

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled by: Takehiko Shimanouchi

Symmetry:   D∞h     Symmetry Number σ = 2


 Sym.   No   Approximate   Selected Freq.  Infrared   Raman   Comments 
 Species   type of mode   Value   Rating   Value  Phase  Value  Phase

σg+ 1 CH str 3374  C  ia 3373.7 S gas
σg+ 2 CC str 1974  C  ia 1973.8 VS gas
σu+ 3 CH str 3289  B 3294.9 S gas  ia FR245)
σu+ 3 CH str 3289  B 3281.9 VS gas  ia FR245)
πg 4 CH bend 612  C  ia 611.8 VW gas
πu 5 CH bend 730  A 730.3 VS gas  ia

Source: Shimanouchi, 1972

Notes

VSVery strong
SStrong
VWVery weak
iaInactive
FRFermi resonance with an overtone or a combination tone indicated in the parentheses.
A0~1 cm-1 uncertainty
B1~3 cm-1 uncertainty
C3~6 cm-1 uncertainty

References

Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, Henry's Law data, Vibrational and/or electronic energy levels, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Chase, 1998
Chase, M.W., Jr., NIST-JANAF Themochemical Tables, Fourth Edition, J. Phys. Chem. Ref. Data, Monograph 9, 1998, 1-1951. [all data]

Manion, 2002
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]

Graul S.T. and Bowers, 1991
Graul S.T.; Bowers, M.T., Dynamics of Metastable Dissociation and Photodissociation of the Gas Phase Cluster Ion (OCS.C2H2)+, J. Phys. Chem., 1991, 95, 21, 8328, https://doi.org/10.1021/j100174a055 . [all data]

Orlando, Friedman, et al., 1990
Orlando, T.M.; Friedman, A.; Maier, J.P., Photodissociation Spectroscopy of the [OCS C2H2]+ Cluster, J. Chem. Phys., 1990, 92, 12, 7365, https://doi.org/10.1063/1.458222 . [all data]

Surya, Ranatunga, et al., 1997
Surya, P.I.; Ranatunga, D.R.A.; Freiser, B.S., Infrared Multiphoton Dissociation of MC4H6+ [M=Fe, Co or Ni: C4H6=1,3-butadiene or (C2H2)(C2H4), J. Am. Chem. Soc., 1997, 119, 14, 3351, https://doi.org/10.1021/ja963200c . [all data]

Armentrout and Kickel, 1994
Armentrout, P.B.; Kickel, B.L., Gas Phase Thermochemistry of Transition Metal Ligand Systems: Reassessment of Values and Periodic Trends, in Organometallic Ion Chemistry, B. S. Freiser, ed, 1994. [all data]

Conn, Kistiakowsky, et al., 1939
Conn, J.B.; Kistiakowsky, G.B.; Smith, E.A., Heats of organic reactions. VIII. Some further hydrogenations, including those of some acetylenes, J. Am. Chem. Soc., 1939, 61, 1868-1876. [all data]

Cox and Pilcher, 1970
Cox, J.D.; Pilcher, G., Thermochemistry of Organic and Organometallic Compounds, Academic Press, New York, 1970, 1-636. [all data]

Walsh and Wells, 1975
Walsh, R.; Wells, J.M., The enthalpy of formation of bicyclo[2,2,1]hepta-2,5-diene. Thermodynamic functions of bicyclo[2,2,1]heptane and bicyclo[2,2,1]hepta-2,5-diene, J. Chem. Thermodyn., 1975, 7, 149-154. [all data]

Pedley, Naylor, et al., 1986
Pedley, J.B.; Naylor, R.D.; Kirby, S.P., Thermochemical Data of Organic Compounds, Chapman and Hall, New York, 1986, 1-792. [all data]

Johnson, van Deventer, et al., 1973
Johnson, G.K.; van Deventer, E.H.; Ackerman, J.P.; Hubbard, W.N.; Osborne, D.W.; Flotow, H.L., J. Chem. Thermodyn., 1973, 5, 57. [all data]

Pedley and Rylance, 1977
Pedley, J.B.; Rylance, J., Computer Analysed Thermochemical Data: Organic and Organometallic Compounds, University of Sussex, Brigton, 1977. [all data]

Ader and Hubbard, 1973
Ader, M.; Hubbard, W.N., J. Chem. Thermodyn., 1973, 5, 607. [all data]

Reppe, Schlichting, et al., 1948
Reppe, W.; Schlichting, O.; Klager, K.; Toepel, T., Cyclisierende Polymerisation von Acetylen I Uber Cyclooctatetraen, Justus Liebigs Ann. Chem., 1948, 1-93. [all data]

Chen and Armetrout, 1995
Chen, Y.M.; Armetrout, P.B., Activation of C2H6, C3H8, and c-C3H6 by Gas-Phase Rh+ and the Thermochemistry of Rh-Ligand Complexes, J. Am. Chem. Soc., 1995, 117, 36, 9291, https://doi.org/10.1021/ja00141a022 . [all data]

Wild, Milley, et al., 2000
Wild, D.A.; Milley, P.J.; Loh, Z.M.; Wolynec, P.P.; Weiser, P.S.; Bieske, E.J., Structural and Energetic Properties of the Br--C2H2 Anion Complex from Rotationally Resolved Mid-infrared Spectra And ab initio Calculations, J. Chem. Phys., 2000, 113, 3, 1075, https://doi.org/10.1063/1.481919 . [all data]

Finch, Gardner, et al., 1991
Finch, A.; Gardner, P.J.; Head, A.J.; Majdi, H.S., Thermochim. Acta, 1991, 180, 325. [all data]

Ervin, Gronert, et al., 1990
Ervin, K.M.; Gronert, S.; Barlow, S.E.; Gilles, M.K.; Harrison, A.G.; Bierbaum, V.M.; DePuy, C.H.; Lin, W.C., Bonds Strengths of Ethylene and Acetylene, J. Am. Chem. Soc., 1990, 112, 15, 5750, https://doi.org/10.1021/ja00171a013 . [all data]

Stockigt, Schwarz, et al., 1996
Stockigt, D.; Schwarz, J.; Schwarz, H., Theoretical and Experimental Studies on the Bond Dissociation Energies of Al(methane)+, Al(acetylene)+, Al(ethene)+, and Al(ethane)+, J. Phys. Chem., 1996, 100, 21, 8786, https://doi.org/10.1021/jp960060k . [all data]

Laursen and Pimentel, 1989
Laursen, S.L.; Pimentel, G.C., Matrix-induced intersystem crossing in the photochemistry of the 1,2-dichloroethenes, J. Phys. Chem., 1989, 93, 2328-2333. [all data]

Lacher, Gottlieb, et al., 1962
Lacher, J.R.; Gottlieb, H.B.; Park, J.D., Reaction heats of organic compounds. Part 2.-Heat of addition of hydrogen chloride to acetylene, Trans. Faraday Soc., 1962, 58, 2348-2351. [all data]

Ono and Ng, 1982
Ono, Y.; Ng, C.Y., A Study of the Unimolecular Decomposition of the (C2H2)2+ Complex, J. Chem. Phys., 1982, 77, 6, 2947, https://doi.org/10.1063/1.444216 . [all data]

Furuyama, Golden, et al., 1968
Furuyama, S.; Golden, D.M.; Benson, S.W., The thermochemistry of the gas-phase equilibria trans-1,2-diiodoethylene = acetylene + I2 and trans-1,2-diiodoethylene = cis-1,2-diiodoethylene, J. Phys. Chem., 1968, 72, 3204-3208. [all data]

Shimanouchi, 1972
Shimanouchi, T., Tables of Molecular Vibrational Frequencies Consolidated Volume I, National Bureau of Standards, 1972, 1-160. [all data]


Notes

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