"Trimethylaluminium is the chemical compound with the formula Al2(CH3)6,
abbreviated as Al2Me6, (AlMe3)2 or the abbreviation TMA. Thispyrophoric, colorless liquid is an industrially important organoaluminium compound. It evolves white smoke (aluminium oxides) when the vapor is released into the air."
"Al2Me6 exists as a dimer, analogous in structure and bonding to diborane. As with diborane, the molecules are connected by 2 3-center-2-electron bonds: the shared methyl groups bridge between the two aluminium atoms. The Al-C(terminal) and Al-C(bridging) distances are 1.97 and 2.14 Å, respectively.[1] The carbon atoms of the bridging methyl groups are each surrounded by five neighbors: three hydrogen atoms and two aluminium atoms. The methyl groups interchange readily intramolecularly and intermolecularly."
"3-Centered-2-electron bonds are an utterance of "electron-deficient" molecules and tend to undergo reactions with Lewis bases that would give products consisting of 2-centered-2-electron bonds. For example upon treatment with amines gives adducts R3N-AlMe3. Another reaction that gives products that follow the octet rule is the reaction of Al2Me6 with aluminium trichloride to give (AlMe2Cl)2."