Carborane acid

Class of chemical compounds

Carborane acids H(CXB11Y5Z6) (X, Y, Z = H, Alk, F, Cl, Br, CF3) are a class of superacids, some of which are estimated to be at least one million times stronger than 100% pure sulfuric acid in terms of their Hammett acidity function values (H0 ≤ −18) and possess computed pKa values well below −20, establishing them as some of the strongest known Brønsted acids. The best-studied example is the highly chlorinated derivative H(CHB11Cl11). The acidity of H(CHB11Cl11) was found to vastly exceed that of triflic acid, CF3SO3H, and bistriflimide, (CF3SO2)2NH, compounds previously regarded as the strongest isolable acids.

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