Bis(trimethyl­ammonium) naphthalene-1,5-disulfonate

The asymmetric unit of the title compound, 2C₃H₁₀N⁺·C₁₀H₆S₂O₆²⁻, contains a half-anion, which is completed by inversion symmetry, and one cation. The cations and anions are associated via strong N—H...O(sulfonate) hydrogen-bonding inter­actions, forming cation–anion–cation groups. Secondary inter­actions such as C—H(ammonium)...O(sulf­on­ate) and van der Waals inter­actions link the cations and anions together in a three-dimensional crystal structure, with zigzag rows of cations lying between layers of anions.

Bis(3-hy­droxy­propanaminium) naphthalene-1,5-disulfonate

In the title molecular salt, 2C₃H₁₀NO⁺·C₁₀H₆O₆S₂²⁻, the cations and anions are associated via N—H...O and O—H...O hydrogen-bonding inter­actions, giving rise to a three-dimensional structure with zigzag rows of cations lying between rows of anions. The asymmetric unit contains one cation and one half-anion, which is related to the remainder of the mol­ecule by an inversion center.

Methyl­ammonium tetra­fluoridoborate 18-crown-6 clathrate

In the title compound, CH₃NH₃⁺·BF₄⁻·C₁₂H₂₄O₆, the methyl­ammonium cation makes three N—H...O hydrogen bonds to the 18-crown-6 mol­ecule. The –NH₃⁺ and –CH₃ groups of the cation adopt a staggered conformation. The F atoms of the tetra­fluoridoborate anion are disordered over two sets of sites in a 0.519 (11):0.481 (11) ratio. Weak C—H...F inter­actions occur in the crystal, which possibly correlate with the anion disorder.

Bis(2-hy­droxy­ethanaminium) terephthalate

The asymmetric unit of the title salt, 2C₂H₈NO⁺·C₈H₄O₄^2-, comprises one crystallographically independent 2-hy­droxy­ethanaminium cation and one half terephthalate anion. In the crystal, hydrogen bonds involving the hy­droxy and ammonium groups of the cations and the carboxyl­ate O atoms of the terephthalate anions result in the formation of a three-dimensional network structure.

2-[(2-Hy­droxy­eth­yl)aza­nium­yl]ethanaminium oxalate monohydrate

In the title hydrated mol­ecular salt, C₄H₁₄N₂O²⁺·C₂O₄²⁻·H₂O, the oxalate dianion is almost planar (r.m.s. deviation = 0.020 Å). In the crystal, the components are linked by N—H...O(water), N—H...O(oxalate) O—H(ammonium)...O(oxalate), O—H(water)...O(oxalate) and O—H(water)...O(ammonium) hydrogen bonds, thereby forming a complex three-dimensional packing motif.

4-{2-[4-(Dimethyl­amino)­phen­yl]ethen­yl}-1-methyl­pyridinium 4-nitro­benzene­sulfonate

The asymmetric unit of the title salt, C₁₆H₁₉N₂⁺. C₆H₄NO₅S⁻, consists of two cations and two anions. The crystal structure is stabilized by π–π inter­actions between the pyridyl and phenyl rings of the cations, with a centroid–centroid distance of 3.7323 (6) Å.

Bis(butan-1-aminium) naphthalene-1,5-disulfonate

In the title compound, 2C₄H₁₂N⁺·C₁₀H₆O₆S₂²⁻, the anion lies on an inversion center, so the asymmetric unit contains half an anion and one cation which are linked by a strong N—H...O hydrogen bond. The crystal structure comprises discrete ions, which are linked into centrosymmetric R₄⁴(12) loops by N—H...O inter­actions.

Propanaminium p-toluene­sulfonate

In the crystal structure of the title salt, C₃H₁₀N⁺·C₇H₇O₃S⁻, N—H...O hydrogen bonds involving the ammonium groups of the cations and the sulfonate O atoms result in the formation of a three-dimensional network.

2-Hy­droxy­pyridinium p-toluene­sulfonate

In the title molecular salt, C₅H₆NO⁺·C₇H₇O₃S⁻, the cations and anions are connected by N—H...O and O—H...O hydrogen bonds, forming [100] chains.

4-(2-Fluoro­benzo­yl)-1-[2-(4-hy­droxy­phen­yl)-2-oxoeth­yl]piperazin-1-ium trifluoro­acetate

In the crystal structure of the title compound, C₁₉H₂₀FN₂O₃⁺·C₂F₃O₂⁻, N—H...O and O—H...O hydrogen bonds link two cations and two anions into a 22-atom ring. These rings are further linked into a three dimensional network by weak C—H...O contacts.