The reactions of sodium sulfide or disulfide with sulfur, when heated, are examined through Raman spectroscopy. It is shown that whatever the composition of the mixtures, the solid sodium sulfide or disulfide transforms into the crystalline alpha-Na(2)S(4) phase in a first step, with alpha- or beta-Na(2)S(2) as an intermediate. The reaction, which proceeds when the sulfur melts, is assumed to be related to the polymerization-depolymerization mechanism responsible for the formation of smaller rings and sulfur chains in molten S(8). This confirms the strong reactivity of the radical sulfur chain molecules. This solid alpha-Na(2)S(4) formed may further react around 200 degrees C with Na(2)S in excess. This solid-state reaction leads to the formation of beta-Na(2)S(2). It is shown that, after the liquid of composition Na(2)S(4) is heated above 400 degrees C, a glass is formed upon cooling. Annealing this glass around 124 degrees C yields a new gamma-Na(2)S(4) crystalline phase where the S(4)(2-) anions have a smaller torsion angle. This new phase is metastable and transforms into the alpha phase upon prolonged heating at 200 degrees C. The solids, formed from heating the mixtures Na(2)S + (n/8)S(8) or Na(2)S(2) + (n'/8)S(8) with n' = n - 1, for n 4, higher polysulfides decompose under crystallization into Na(2)S(5) and sulfur. The liquids formed from these mixtures show the formation of all the S(n)()(+1)(2-) anions although Na(2)S(3) and Na(2)S(6) do not crystallize from these liquids.

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It is evidenced through vibrational spectroscopy that a heterodimer or "Quadac" is formed when an excess of base (LHMDS, LDA, or n-BuLi) is added to PhCH(2)CN in THF, THF-hexane, or THF-toluene solution. The amount of heterodimer increases with the pK(H)(a) of the lithiated base. A dianionic species may be formed through decomposition of this heterodimer if the pK(H)(a) of the base is sufficiently high, as in the case of n-BuLi. With LDA, only a very small amount of dianion is observed, and with LHMDS, no dianion is detected. The predominant dianionic species observed are the linear and bridged separated ion pairs of the dilithiated dianion. The presence of the amine in the medium is of paramount importance. The PhCHCNLi monomer-dimer equilibrium is entropy driven toward the dimer solvated by the amine.