Sodide Solids

We saw in Section 6.6 that the reaction of solid sodium with gaseous chlorine to yield solid sodium chloride (Na+Cl-) is favorable by 411 kj/mol. Calculate the energy change for the alternative reaction that yields chlorine sodide (Cl+Na ), and then explain why sodium chloride formation is preferred. 

The study of more concentrated alkali metal solutions in a variety of solvents became possible in 1970, when crown ethers were used to enhance the solubility of the metal. The use of crown ethers and cryptands permitted extensive studies of the optical spectra of solvated electrons and alkali metal anions in solution. After the isolation of the first sodide salt in 1974, the optical spectra of polycrystalline films of various alkalides and electrides were determined by rapid evaporation of all solvent from a liquid film on the walls of the optical cell." " Displayed in Fig. 1 are the optical spectra obtained in this way. Clearly, there is a 1 1 correspondence between the spectra in solution and in the solid state. Although the peak positions shift somewhat with temperature and with the complexant used, the optical peaks can be used to verify the presence of particular alkali metal anions or trapped electrons. In addition to rapid solvent evaporation, solvent-free alkalide and electride films can be made by codeposition of the complexant and alkali metal in high vacuum (10 torr)." This permitted the study of optical... 

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