Crystalline carboxylic acids adipic acid

Now we apply the theoretical methods presented above to reproduce the experimental spectra of some carboxylic acids. This section is devoted to such tests dealing with carboxylic acids. These acids are acetic, acrylic, propynoic, adipic, glutaric, and naphtoic acid. The different phases will be the gaseous, liquid, and crystalline states. 

In conclusion, note that the quality of the theoretical SD with respect to the experimental line shape is not as good for crystalline adipic acid as for the gaseous and liquid carboxylic acids studied above. The reason is that if Fermi resonances seem to be unavoidable in order to reproduce all features of the experimental line shapes and to conserve a good stability of the basic physical parameters when changing the temperature, however, the way in which the Fermi resonances are taken into account is very sentitive to the used adiabatic and exchange approximations [82]. 

Malonate and the dianions of the other aliphatic dicarboxylic acids H02 C(CH2 ) CO,H (n = 1-8) have been isolated as crystalline hydrates, and some of these have been dehydrated.293 X-Ray structural analyses have been reported for the malonate dihydrate,294 which has trans H2Os and bridging malonates of type (110), and for the succinate tetrahydrate and adipate dihydrate 295 the succinate reputedly has a trans- fAn02 (H2 0)4 ] polyhedron with bridging dicarboxylate, presumably as in (109). The monoanion of maleic acid (111) is only unidentate in crystalline [Mn(H-maleate)2-(H20)4] 296 but the equivalent compound of phthalic acid is a bis-chelated octahedral [Mn(0,0)2 (H2 0)2] species.297 Clearly other interactions in the solids, as well as the bonding interactions with Mn", define structure in the carboxylate compounds. 

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