Bis(4-amino­pyridinium) hexa­aqua­nickel(II) bis­(sulfate)

In the title compound, (C₅H₇N₂)₂[Ni(H₂O)₆](SO₄)₂, the Ni^II cation is located on an inversion centre and is coordinated by six aqua ligands in a slightly distorted octa­hedral coordination environment. The [Ni(H₂O)₆]²⁺ ions are connected through an extensive network of O—H...O hydrogen bonds to sulfate anions, leading to the formation of layers parallel to (001). The 4-amino­pyridinium cations are located between these layers and are connected to the anionic framework by N—H...O hydrogen bonds. Weak π–π inter­actions between the pyridine rings, with a centroid–centroid distance of 3.754 (9) Å, provide additional stability to the crystal packing.

1-Phenyl­piperazine-1,4-diium tetra­chlorido­cobalt(II)

In the title mol­ecular salt, (C₁₀H₁₆N₂)[CoCl₄], the piperazine ring of the phenyl­piperazine dication adopts a chair conformation and the phenyl ring occupies an equatorial orientation. In the tetra­chlorido­cobaltate(II) dianion, the Co—Cl bond lengths for the chloride ions not accepting hydrogen bonds are significantly shorter than those for the chloride ions accepting such bonds. In the crystal, the components are linked by N—H...Cl hydrogen bonds, generating [001] chains.

Tri­chlorido­(1-ethyl­piperazin-1-ium)cobalt(II)

In the title complex, [Co(C₆H₁₅N₂)Cl₃], the Co²⁺ ion is coordinated in a distorted tetra­hedral fashion by three chloride ions and one N atom of the piperazine ring; the ring adopts a chair conformation with the N—Co and N—C_Et bonds in equatorial orientations. In the crystal, mol­ecules are connected by N—H...Cl hydrogen bonds, generating (10-1) sheets.

Crystal structure of 2,5-di­methyl­anilinium hydrogen maleate

The crystal structure of the title salt, C₈H₁₂N⁺·C₄H₃O₄⁻, consists of a 2,5-di­methyl­anilinium cation and an hydrogen maleate anion. In the anion, a strong intra­molecular O—H...O hydrogen bond is observed, leading to an S(7) graph-set motif. In the crystal, the cations and anions pack in alternating layers parallel to (001). The ammonium group undergoes inter­molecular N—H...O hydrogen-bonding inter­actions with the O atoms of three different hydrogen maleate anions. This results in the formation of ribbons extending parallel to [010] with hydrogen-bonding motifs of the types R⁴₄(12) and R⁴₄(18).