The title compound, 2C5H7N5(2+)·2HSO4(-)·SO4(2-), was synthesized from adenine and sulfuric acid. The asymmetric unit contains two diprotonated adeninium cations, two bis-ulfate anions and one sulfate anion. The crystal structure is stabilized by classical N-H⋯O and O-H⋯O hydrogen bonds, and weak C-H⋯O and C-H⋯N hydrogen bonds, generating a three-dimensional network.

Aqueous H2O2 is an ideal oxidant, when coupled with a tungstate complex and a quaternary ammonium hydrogensulfate as an acidic phase-transfer catalyst. It oxidizes alcohols, olefins, and sulfides under organic solvent- and halide-free conditions in an economically, technically, and environmentally satisfying manner.

The title compound, [Cu(2)(C(13)H(9)N(4))(2)(HSO(4))(2)]·2CH(3)OH, consists of discrete centrosymmetric dinuclear complex mol-ecules and methanol solvent mol-ecules. The Cu(II) atom shows a square-pyramidal coordination geometry and is bonded to four N atoms of the two bis-chelating 3,5-bis-(2-pyrid-yl)pyrazol-ate ions (bpypz(-)) and one O atom of the hydrogensulfate ion. The bpypz(-) ligands i...

The title compound, C(5)H(10)NO(+)·HSO(4) (-), has been synthesized by reaction of 1-methyl-pyrrolidin-2-one with H(2)SO(4) in a 1:1 molar ratio. The substituted pyrrolium ring adopts an envelope conformation. The hydrogensulfate anions form infinite helical chains parallel to the a axis via strong O-H⋯O hydrogen bonds. The pyrrolium cations are pendant from the chains. These cations are the hy...

In the title compound, C(9)H(20)NO(+)·HO(4)S(-)·H(2)O, the piperi-dinium ring adopts a chair conformation. Inter-molecular O-H⋯O and N-H⋯O hydrogen bonds form an extensive three-dimensional network, which consolidates the crystal structure.

In the title compound, C(10)H(11)N(2) (+)·HSO(4) (-)·2H(2)O, the asymmetric unit contains two protonated 4-amino-quinoline cations and two hydrogen sulfate anions with four water mol-ecules. The crystal structure involves extensive N-H⋯O and O-H⋯O hydrogen bonding.