Trimethylaluminum
- Formula: C3H9Al
- Molecular weight: 72.0851
- IUPAC Standard InChI: InChI=1S/3CH3.Al/h3*1H3;
- IUPAC Standard InChIKey: JLTRXTDYQLMHGR-UHFFFAOYSA-N
- CAS Registry Number: 75-24-1
- Chemical structure:
This structure is also available as a 2d Mol file or as a computed 3d SD file
The 3d structure may be viewed using Java or Javascript. - Other names: (CH3)3Al; Aluminum, trimethyl-; Trimethylalane; Trimethylaluminium; UN 1103
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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 by: José A. Martinho Simões
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔfH°gas | -86.5 ± 4.8 | kJ/mol | Review | Martinho Simões | Selected data. The enthalpy of formation relies on -1891.3 ± 1.9 kJ/mol for the enthalpy of formation of Al(OOCMe)3(cr) and on 0.9 ± 0.2 kJ/mol for the enthalpy of solution of MeCOOH(l) in toluene Mortimer and Sellers, 1963. Liquid trimethylaluminum contains a very small molar fraction of monomer at 298 K, ca. 0.007% Smith, 1972, so that the "real" liquid should be described as [Al(Me)3]2. |
| ΔfH°gas | -57.0 ± 9.7 | kJ/mol | Review | Martinho Simões | Liquid trimethylaluminum contains a very small molar fraction of monomer at 298 K, ca. 0.007% Smith, 1972, so that the "real" liquid should be described as [Al(Me)3]2. |
| ΔfH°gas | -88.7 | kJ/mol | Review | Martinho Simões | The enthalpy of formation was quoted from Smith, 1974 and relies on experimental data in Tröber and Stricker, 1966. Liquid trimethylaluminum contains a very small molar fraction of monomer at 298 K, ca. 0.007% Smith, 1972, so that the "real" liquid should be described as [Al(Me)3]2. |
Condensed 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:
MS - José A. Martinho Simões
DH - Eugene S. Domalski and Elizabeth D. Hearing
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔfH°liquid | -149.7 ± 4.5 | kJ/mol | Review | Martinho Simões | Selected data. The enthalpy of formation relies on -1891.3 ± 1.9 kJ/mol for the enthalpy of formation of Al(OOCMe)3(cr) and on 0.9 ± 0.2 kJ/mol for the enthalpy of solution of MeCOOH(l) in toluene Mortimer and Sellers, 1963. Liquid trimethylaluminum contains a very small molar fraction of monomer at 298 K, ca. 0.007% Smith, 1972, so that the "real" liquid should be described as [Al(Me)3]2.; MS |
| ΔfH°liquid | -120.2 ± 9.6 | kJ/mol | Review | Martinho Simões | Liquid trimethylaluminum contains a very small molar fraction of monomer at 298 K, ca. 0.007% Smith, 1972, so that the "real" liquid should be described as [Al(Me)3]2.; MS |
| ΔfH°liquid | -151.9 | kJ/mol | CC-SB | Smith, 1974 | Value corrected based on a set of ancillary data by J.A. Martinho Simões; The enthalpy of formation was quoted from Smith, 1974 and relies on experimental data in Tröber and Stricker, 1966. Liquid trimethylaluminum contains a very small molar fraction of monomer at 298 K, ca. 0.007% Smith, 1972, so that the "real" liquid should be described as [Al(Me)3]2.; MS |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔcH°liquid | -3184.4 ± 9.6 | kJ/mol | CC-SB | Long and Norrish, 1949 | Please also see Cox and Pilcher, 1970. Liquid trimethylaluminum contains a very small molar fraction of monomer at 298 K, ca. 0.007% Smith, 1972, so that the "real" liquid should be described as [Al(Me)3]2.; MS |
| Quantity | Value | Units | Method | Reference | Comment |
| S°liquid | 209.41 | J/mol*K | N/A | McCullough, Messerly, et al., 1963 | DH |
Constant pressure heat capacity of liquid
| Cp,liquid (J/mol*K) | Temperature (K) | Reference | Comment |
|---|---|---|---|
| 155.60 | 298.15 | McCullough, Messerly, et al., 1963 | T = 10 to 380 K.; DH |
Phase change 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:
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director
MS - José A. Martinho Simões
AC - William E. Acree, Jr., James S. Chickos
DH - Eugene S. Domalski and Elizabeth D. Hearing
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| Ttriple | 288.43 | K | N/A | McCullough, Messerly, et al., 1963, 2 | Uncertainty assigned by TRC = 0.02 K; TRC |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔvapH° | 63.2 ± 1.7 | kJ/mol | RSC | McCullough, Messerly, et al., 1963, 2 | MS |
Enthalpy of vaporization
| ΔvapH (kJ/mol) | Temperature (K) | Reference | Comment |
|---|---|---|---|
| 43.0 | 288. to 293. | Fulem, Ruzicka, et al., 2003 | AC |
| 39.8 | 351. | McCullough, Messerly, et al., 1963 | Based on data from 336. to 400. K.; AC |
Antoine Equation Parameters
log10(P) = A − (B / (T + C))
P = vapor pressure (bar)
T = temperature (K)
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| Temperature (K) | A | B | C | Reference | Comment |
|---|---|---|---|---|---|
| 336.96 to 400.27 | 4.67984 | 1724.231 | -31.398 | McCullough, Messerly, et al., 1963 | Coefficents calculated by NIST from author's data. |
Enthalpy of sublimation
| ΔsubH (kJ/mol) | Temperature (K) | Reference | Comment |
|---|---|---|---|
| 60.1 | 243. to 285. | Fulem, Ruzicka, et al., 2003 | AC |
Enthalpy of fusion
| ΔfusH (kJ/mol) | Temperature (K) | Reference | Comment |
|---|---|---|---|
| 8.7906 | 288.43 | McCullough, Messerly, et al., 1963 | DH |
| 8.79 | 288.4 | Domalski and Hearing, 1996 | AC |
Entropy of fusion
| ΔfusS (J/mol*K) | Temperature (K) | Reference | Comment |
|---|---|---|---|
| 30.48 | 288.43 | McCullough, Messerly, et al., 1963 | DH |
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
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
+
= (
•
)
By formula: H- + C3H9Al = (H- • C3H9Al)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | >354.8 ± 2.1 | kJ/mol | IMRB | den Berg, Ingemann, et al., 1992 | gas phase; Hydride affinity > (CF3)2CO. Computations indicate HOF(A-) ca. -46 kcal/mol, dHaff ca. 74 kcal/mol; B |
C6H18Al2 (l) = 2 (l)
By formula: C6H18Al2 (l) = 2C3H9Al (l)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 81.2 ± 1.3 | kJ/mol | EqS | Smith, 1972 | MS |
Gas phase ion energetics 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:
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron
Ionization energy determinations
| IE (eV) | Method | Reference | Comment |
|---|---|---|---|
| 9.09 ± 0.26 | EI | Winters and Kiser, 1967 | RDSH |
| 9.76 | PE | Barker, Lappert, et al., 1975 | Vertical value; LLK |
Appearance energy determinations
| Ion | AE (eV) | Other Products | Method | Reference | Comment |
|---|---|---|---|---|---|
| Al+ | 14.6 ± 0.2 | ? | EI | Winters and Kiser, 1967 | RDSH |
| CH3Al+ | 13.9 ± 0.3 | ? | EI | Winters and Kiser, 1967 | RDSH |
| C2H6Al+ | 10.1 ± 0.3 | CH3 | EI | Winters and Kiser, 1967 | RDSH |
Ion clustering 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: John E. Bartmess
Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. Searches may be limited to ion clustering reactions. A general reaction search form is also available.
Clustering reactions
+
= (
•
)
By formula: H- + C3H9Al = (H- • C3H9Al)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | >354.8 ± 2.1 | kJ/mol | IMRB | den Berg, Ingemann, et al., 1992 | gas phase; Hydride affinity > (CF3)2CO. Computations indicate HOF(A-) ca. -46 kcal/mol, dHaff ca. 74 kcal/mol |
Mass spectrum (electron ionization)
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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: NIST Mass Spectrometry Data Center, William E. Wallace, director
Spectrum
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Additional Data
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| Owner | NIST Mass Spectrometry Data Center Collection (C) 2014 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved. |
|---|---|
| Origin | Chemical Concepts |
| NIST MS number | 151727 |
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: Marilyn E. Jacox
State: X
Additional references: Jacox, 1994, page 400
Notes
| w | Weak |
| m | Medium |
| s | Strong |
| vs | Very strong |
| T | Tentative assignment or approximate value |
References
Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, Gas phase ion energetics data, Ion clustering data, Mass spectrum (electron ionization), 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.
Martinho Simões
Martinho Simões, J.A.,
Private communication (see http://webbook.nist.gov/chemistry/om/). [all data]
Mortimer and Sellers, 1963
Mortimer, C.T.; Sellers, P.,
J. Chem. Soc., 1963, 1978.. [all data]
Smith, 1972
Smith, M.B.,
J. Organometal. Chem., 1972, 46, 31. [all data]
Smith, 1974
Smith, M.B.,
J. Organometal. Chem., 1974, 76, 171. [all data]
Tröber and Stricker, 1966
Tröber, A.; Stricker, C.,
Wiss Z. Tech. Hochsch. Chem. "Carl Schlorlemmer" Leuna-Merseburg, 1966, 8, 34. [all data]
Long and Norrish, 1949
Long, L.H.; Norrish, R.G.W.,
Phil. Trans. Roy. Soc. (London), 1949, A241, 587. [all data]
Cox and Pilcher, 1970
Cox, J.D.; Pilcher, G.,
Thermochemistry of Organic and Organometallic Compounds
in Academic Press, New York, 1970. [all data]
McCullough, Messerly, et al., 1963
McCullough, J.P.; Messerly, J.F.; Moore, R.T.; Todd, S.S.,
Trimethylaluminum: thermodynamic functions in the solid and liquid states, 0-380°K, vapor pressure, heat of vaporization, and entropy in the ideal gas state,
J. Phys. Chem., 1963, 67, 677-679. [all data]
McCullough, Messerly, et al., 1963, 2
McCullough, J.P.; Messerly, J.F.; Moore, R.T.; Todd, S.S.,
J. Phys. Chem., 1963, 67, 677. [all data]
Fulem, Ruzicka, et al., 2003
Fulem, M.; Ruzicka, K.; Ruzicka, V.; Hulicius, E.; Simecek, T.; Melichar, K.; Pangrác, J.; Rushworth, S.A.; Smith, L.M.,
Vapor pressure of metal organic precursors,
Journal of Crystal Growth, 2003, 248, 99-107, https://doi.org/10.1016/S0022-0248(02)01840-7
. [all data]
Domalski and Hearing, 1996
Domalski, Eugene S.; Hearing, Elizabeth D.,
Heat Capacities and Entropies of Organic Compounds in the Condensed Phase. Volume III,
J. Phys. Chem. Ref. Data, 1996, 25, 1, 1, https://doi.org/10.1063/1.555985
. [all data]
den Berg, Ingemann, et al., 1992
den Berg, K.J. van; Ingemann, S.; Nibbering, N.M.M.,
Gas Phase Reactions of Negative Ions with Trimethylaluminum: Formation and Reactivity of the Me3AlH- Ion.,
Org. Mass Spectrom., 1992, 27, 4, 523, https://doi.org/10.1002/oms.1210270427
. [all data]
Winters and Kiser, 1967
Winters, R.E.; Kiser, R.W.,
Ionization and fragmentation of dimethylzinc, trimethylaluminum, and trimethylantimony,
J. Organometal. Chem., 1967, 10, 7. [all data]
Barker, Lappert, et al., 1975
Barker, G.K.; Lappert, M.F.; Pedley, J.B.; Sharp, G.J.; Westwood, N.P.C.,
Bonding studies of boron and the group 3-5 elements. Part XV. He(I) photoelectron spectra of monomeric group 3 tri-halide, trimethyl, and mixed halogenomethyl species,
J. Chem. Soc. Dalton Trans., 1975, 1765. [all data]
O'Brien and Ozin, 1971
O'Brien, R.J.; Ozin, G.A.,
J. Chem. Soc. A, 1971, 1136. [all data]
Kvisle and Rytter, 1984
Kvisle, S.; Rytter, E.,
Spectrochim. Acta 40A, 1984, 939. [all data]
Atiya, Grady, et al., 1991
Atiya, G.A.; Grady, A.S.; Russell, D.K.; Claxton, T.A.,
Spectrochim. Acta, 1991, 47A, 467. [all data]
Jacox, 1994
Jacox, M.E.,
Vibrational and electronic energy levels of polyatomic transient molecules, American Chemical Society, Washington, DC, 1994, 464. [all data]
Notes
Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, Gas phase ion energetics data, Ion clustering data, Mass spectrum (electron ionization), Vibrational and/or electronic energy levels, References
- Symbols used in this document:
AE Appearance energy Cp,liquid Constant pressure heat capacity of liquid S°liquid Entropy of liquid at standard conditions Ttriple Triple point temperature ΔcH°liquid Enthalpy of combustion of liquid at standard conditions ΔfH°gas Enthalpy of formation of gas at standard conditions ΔfH°liquid Enthalpy of formation of liquid at standard conditions ΔfusH Enthalpy of fusion ΔfusS Entropy of fusion ΔrH° Enthalpy of reaction at standard conditions ΔrS° Entropy of reaction at standard conditions ΔsubH Enthalpy of sublimation ΔvapH Enthalpy of vaporization ΔvapH° Enthalpy of vaporization at standard conditions - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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