Organosodium chemistry is the chemistry of organometallic compounds containing a carbon to sodium chemical bond. The application of organosodium compounds in chemistry is limited in part due to competition from organolithium compounds, which are commercially available and exhibit more convenient reactivity.
The principal organosodium compound of commercial importance is sodium cyclopentadienide. Sodium tetraphenylborate can also be classified as an organosodium compound since in the solid state sodium is bound to the aryl groups.
Organometal bonds in group 1 are characterised by high polarity with corresponding high nucleophilicity on carbon. This polarity results from the disparate electronegativity of carbon (2.55) and that of lithium 0.98, sodium 0.93 potassium 0.82 rubidium 0.82 caesium 0.79). The carbanionic nature of organosodium compounds can be minimized by resonance stabilization, for example, Ph3CNa. One consequence of the highly polarized Na-C bond is that simple organosodium compounds often exist as polymers that are poorly soluble in solvents.
In the original work the alkylsodium compound was accessed from the dialkylmercury compound by transmetallation. For example, diethylmercury in the Schorigin reaction or Shorygin reaction:
The high solubility of lithium alkoxides in hexane is the basis of a useful synthetic route:
For some acidic organic compounds, the corresponding organosodium compounds arise by deprotonation. Sodium cyclopentadienide is thus prepared by treating sodium metal and cyclopentadiene: