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 | -20.7 ± 1.1 | kcal/mol | Review | Martinho Simões | Selected data. The enthalpy of formation relies on -452.03 ± 0.45 kcal/mol for the enthalpy of formation of Al(OOCMe)3(cr) and on 0.2 ± 0.05 kcal/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 | -13.6 ± 2.3 | kcal/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 | -21.2 | kcal/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 | -35.8 ± 1.1 | kcal/mol | Review | Martinho Simões | Selected data. The enthalpy of formation relies on -452.03 ± 0.45 kcal/mol for the enthalpy of formation of Al(OOCMe)3(cr) and on 0.2 ± 0.05 kcal/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 | -28.7 ± 2.3 | kcal/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 | -36.30 | kcal/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 | -761.1 ± 2.3 | kcal/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 | 50.050 | cal/mol*K | N/A | McCullough, Messerly, et al., 1963 | DH |
Constant pressure heat capacity of liquid
| Cp,liquid (cal/mol*K) | Temperature (K) | Reference | Comment |
|---|---|---|---|
| 37.189 | 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° | 15.1 ± 0.41 | kcal/mol | RSC | McCullough, Messerly, et al., 1963, 2 | MS |
Enthalpy of vaporization
| ΔvapH (kcal/mol) | Temperature (K) | Reference | Comment |
|---|---|---|---|
| 10.3 | 288. to 293. | Fulem, Ruzicka, et al., 2003 | AC |
| 9.51 | 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 (atm)
T = temperature (K)
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| Temperature (K) | A | B | C | Reference | Comment |
|---|---|---|---|---|---|
| 336.96 to 400.27 | 4.67413 | 1724.231 | -31.398 | McCullough, Messerly, et al., 1963 | Coefficents calculated by NIST from author's data. |
Enthalpy of sublimation
| ΔsubH (kcal/mol) | Temperature (K) | Reference | Comment |
|---|---|---|---|
| 14.4 | 243. to 285. | Fulem, Ruzicka, et al., 2003 | AC |
Enthalpy of fusion
| ΔfusH (kcal/mol) | Temperature (K) | Reference | Comment |
|---|---|---|---|
| 2.1010 | 288.43 | McCullough, Messerly, et al., 1963 | DH |
| 2.10 | 288.4 | Domalski and Hearing, 1996 | AC |
Entropy of fusion
| ΔfusS (cal/mol*K) | Temperature (K) | Reference | Comment |
|---|---|---|---|
| 7.285 | 288.43 | McCullough, Messerly, et al., 1963 | DH |
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 |
References
Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Gas phase ion energetics data, 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]
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]
Notes
Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Gas phase ion energetics data, 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 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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