Thallium alkyl compounds

Thallium compounds analogous to the aluminium tri-alkyls have not yet been prepared, but numerous compounds of the type Tl(Alkyl)₂X are known. They must be looked upon as binary electrolytes, which dissociate thus: -

Tl(Alkyl)₂X ⇔ Tl(Alkyl)₂^• + X',

a view in accordance with the conductivities of their solutions, and with the fact that they are quite stable towards boiling aqueous ammonia and alkali hydroxides.

The thallium alkyl chlorides are readily prepared by the general reaction: -

TlCl₃ + 2Mg.Alkyl.Cl = Tl(Alkyl)₂Cl + 2MgCl₂,

the reagents being mixed in dry ethereal solution. The bromides, iodides, carbonates, etc., may then be prepared by double decomposition. The salts crystallise well, and are only sparingly soluble in water. The hydroxides are strong bases, and readily absorb carbon dioxide. The alkyl compounds thus bear a great resemblance to the thallous compounds.