Tetrakis(2,6-di­methyl­pyridinium) di­hydrogen deca­vanadate dihydrate

The structure of the title compound, (C₇H₁₀N)₄[H₂V₁₀O₂₈]·2H₂O, was solved from a non-merohedrally twinned crystal (ratio of twin components ∼0.6:0.4). The asymmetric unit consists of one-half deca­vanadate anion (the other half completed by inversion symmetry), two 2,6-di­methyl­pyridinium cations and one water mol­ecule of crystallization. In the crystal, the components are connected by strong N—H...O and O—H...O hydrogen bonds, forming a supra­molecular chain along the b-axis direction. There are weak C—H...O inter­actions between the chains.

catena-Poly[[(pyrazine-2-carboxamide-κN⁴)copper(I)]-μ₃-iodido]

In the title metal–organic polymeric complex, [CuI(C₅H₅N₃O)]_n, the asymmetric unit is composed of one monomer unit of the polymer and one Cu^I atom linked to one iodide anion and one pyrazine-2-carboxamide mol­ecule. The Cu^I atom is in a distorted tetra­hedral coordination completed by one pyrazine N atom of the pyrazine-2-carboxamide ligand and three iodide anions. The polymeric structure adopts a well-known ladder-like motif of {CuNI₃} tetra­hedra running in the b-axis direction. The mol­ecules of the organic ligand are connected via medium-to-strong N—H...O and N—H...N hydrogen bonds and weak π–π inter­actions [the distance between two parallel planes of the rings is 3.5476 (14) Å and the centroid–centroid contact is 4.080 (2) Å]. The title compound has a relatively high decomposition temperature (564 K) as a result of relatively strong covalent and non-covalent inter­actions inside and between the chains.