Carbonate dianion

Figure 1.3 A calculated electrostatic potential map for carbonate dianion, showing the equal charge distribution at the three oxygen atoms. In electrostatic potential maps like this one, colors trending toward red mean increasing concentration of negative charge, while those trending toward blue mean less negative (or more positive) charge.

The UV-visible and NMR spectra have revealed that the charge on the disilanylene 1,2-dianion derived from dimetallation of l,2-chloro-l,2-disilaacenaphthene is much less delocalized than the corresponding carbon dianion, but more delocalized than for phenylsilyl anions.10 Persilylated dimethylenecyclobutene has been reduced by lithium metal in 1,2-dimethoxyethene to give the first reported 6C-8re allyl anion system, persilylated dimethylenecyclobutene dianion dilithium 11 the six carbon atoms of the n-... 

Sodium carbonate (Na2C03) has been used in detergent formulations for many years both to sequester calcium ions (at pH > 9) in the wash water and as an alkalinity source. The structure of the carbonate dianion is shown in Figure 9.4. Currently, all powder ADDs contain high levels of sodium carbonate (15 to 40%), mainly as a source of alkalinity. In LADDs, where caustic can be incorporated into the compositions, the need for sodium carbonate is less important. 

The more nearly equivalent the resonance contributors are in structure, the greater The more nearly equivalent the is the resonance energy. The carbonate dianion is particularly stable because it has resonance contributors are in structure, three equivalent resonance contributors. greater is the resonance energy. 

The eventual alternative extraction mechanism in such systems can be excluded on the basis of experimental observations and also a priori reasoning. Thus, when a suspension of K2CO3 in a moderately polar solvent, e.g., acetonitrile, is treated with a TAA salt no basic anions are transferred into the organic solution. Since strongly basic carbonate dianions are much less lipophilic than bicarbonate anions, which are much weaker bases, and only the latter ions could eventually enter the organic solution, transfer of these could not be the pathway for deprotonation of the carbanion precursors. 

Cyanide anion Thiocyanate anion Azide anion Nitro anion Carbonate dianion Imidazolate Dimethylsulfoxide Ethylendiamine (en)... 

Figure 12 A representation of the structure of the V15 (9) shell encapsulating a carbonate dianion. The vanadium ions are shown as black spheres and the oxygen atoms as white spheres. The carbon atom of the...

Carbonic anhydrase is an enzyme that interconverts water and carbon dioxide with carbonic acid. A carbonate dianion is shown in red within the structure of carbonic anhydrase above. 

For example, the carbonate dianion is particularly stable because it has three equivalent resonance contributors. 

Because of the electron-accepting nature of the carbonyl group, the fluorines attached to the aromatic rings can be substituted by the carbonate dianion (review Section 13.4 if necessary) ... 

The absence of catalytic cleavage of nonionized phthalimide in the presence of carbonate buffer solution cannot be attributed to the steric requirement of carbonate dianion, because trimethylamine and DABCO may be considered to have the same or even more steric requirements than carbonate dianion. The most... 

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