It is a solution of Lithium Naphthalenide, and it is a compound similar to sodium naphthalenide in tetrahydrofuran medium. Tetrahydrofuran and its isotopes such as Lithium Naphtalenide are used as a reductant in organic synthesis, and it is directly prepared before applying in usual.
Sodium Naphthalenide is prepared by interacting metallic sodium with naphthalene in an ethereal solvent such as Tetrahydrofuran or Dimethoxyethane. Sodium Naphthalenide is a dark green solid. This color comes from absorption at 463.735 nm. The negative ion it contains (the anion) is a free root which has a signal in electron magnetic resonance (EPR). This anion is characterized by being a strong alkaline, and it reacts with water to give Dihydrnaphthalene.