Propane-1,2-di­ammonium chromate(VI)

In the title mol­ecular salt, (C₃H₁₂N₂)[CrO₄], each chromate anion accepts six N—H...O and C—H...O hydrogen bonds from nearby propane-1,2-di­ammonium cations. Three of the four O atoms of the chromate anion accept these bonds; the remaining Cr—O bond length is notably shorter than the others. In the crystal, the anions and cations stack in layers lying parallel to (100): the hydrogen-bonding pattern leads to a three-dimensional network.

Bis(1-methyl­piperazine-1,4-diium) di-μ-bromido-bis­[tetra­bromido­bismuthate(III)] dihydrate

In the title hydrated salt, (C₅H₁₄N₂)₂[Bi₂Br₁₀]·2H₂O, the com­plete [Bi₂Br₁₀]⁴⁻ biocta­hedron is generated by crystallographic inversion symmetry. The diprotonated piperazine ring adopts a chair conformation, with the methyl group occupying an equatorial position. In the crystal, the tetra­anions and water mol­ecules are linked by O—H...Br and O—H...(Br,Br) hydrogen bonds to generate [100] chains. The chains are crosslinked by N—H...Br, N—H...O and C—H...Br hydrogen bonds originating from the piperazinediium dications, thereby forming a three-dimensional network.

1-Methyl­piperazine-1,4-dium bis­(hydrogen oxalate)

In the crystal structure of the title compound, C₅H₁₄N₂²⁺·2HC₂O₄⁻, the two crystallographically independent hydrogen oxalate anions are linked by strong inter­molecular O—H...O hydrogen bonds, forming two independent corrugated chains parallel to the b axis. These chains are further connected by N—H...O and C—H...O hydrogen bonds originating from the organic cations, forming a three-dimensional network. The diprotonated piperazine ring adopts a chair conformation, with the methyl group occupying an equatorial position.