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. |
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° | >84.80 ± 0.50 | kcal/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° | 19.4 ± 0.31 | kcal/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° | >84.80 ± 0.50 | kcal/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 |
References
Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, Gas phase ion energetics data, Ion clustering 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]
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]
Notes
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- Symbols used in this document:
AE Appearance energy ΔfH°gas Enthalpy of formation of gas at standard conditions ΔrH° Enthalpy of reaction at standard conditions ΔrS° Entropy of reaction at standard conditions - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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