catena-Poly[[[aqua­(pyrazine-2-carboxamide-κ2 N 1,O)zinc]-μ-pyrazine-2-carboxamide-κ3 N 1,O:N 4] dinitrate]

In the crystal of the title compound, {[Zn(C5H5N3O)2(H2O)](NO3)2}n, the ZnII cation is N,O-chelated by two pyrazine-2-carboxamide (PCA) ligands and is further coordinated by one water mol­ecule and by one pyrazine-N atom from an adjacent PCA ligand in a distorted ZnN3O3 octa­hedral geometry. One of the two independent PCA ligands bridges two ZnII cations, forming a zigzag polymeric chain running along the c axis. In the crystal, the NO3 − anions link to the chain via O—H⋯O and N—H⋯O hydrogen bonding. Weak inter­molecular C—H⋯O inter­actions also occur

catena-Poly[[diiodidomercury(II)]-μ2-2-amino­pyrazine-κ2 N 1:N 4]

In the crystal of the title polymeric compound, [HgI2(C4H5N3)]n, the HgII cation is located on a twofold rotation axis and is coordinated by two I− anions and two 2-amino­pyrazine ligands in a distorted HgI2N2 tetra­hedral geometry. In the crystal, the 2-amino­pyrazine ligand is equally disordered over two positions about an inversion center, and bridges the HgII cations with pyrazine N atoms to form a polymeric chain running along the c axis. In the polymeric chain, the amino groups link to the coordinated I− anions via inter­molecular N—H⋯I hydrogen bonds

catena-Poly[[bis­(pyridine-3-carb­oxy­lic acid-κN)mercury(II)]-di-μ-chlorido]

In the title compound, [HgCl2(C6H5NO2)2]n, the HgII cation is located on an inversion center and is six-coordinated in a distorted octa­hedral geometry by two N atoms from two pyridine-3-carb­oxy­lic acid mol­ecules and four bridging Cl− anions. The bridging function of the Cl− anions leads to polymeric chains running along the a axis. One Hg—Cl bond is much longer than the other. In the crystal, O—H⋯O and weak C—H⋯Cl hydrogen bonds are observed

Dibromidobis(pyrazine-2-carboxamide-κN 4)zinc

The title complex, [ZnBr2(C5H5N3O)2], shows crystallographic mirror symmetry with the Zn atom and the two bromine ligands located on the mirror plane. The Zn atom is four-coordinated in a distorted tetra­hedral fashion by two N atoms from two pyrazine-2-carboxamide ligands and two Br atoms. Only one of the amino H atoms is involved in an N—H⋯O hydrogen bond. The crystal packing is further stabilized by weak N—H⋯N and C—H⋯O inter­actions

Dichloridobis(pyrazine-2-carboxamide-κN 4)zinc(II)

In the crystal of the title compound, [ZnCl2(C5H5N3O)2], the mol­ecule has m symmetry, with the ZnII cation and Cl− anions located on the mirror plane. The ZnII cation is coordinated by two Cl− anions and two pyrazine-2-carboxamide ligands in a distorted ZnCl2N2 tetra­hedral geometry. The two pyrazine rings are nearly perpendicular to each other [dihedral angle = 86.61 (10)°]. Inter­molecular N—H⋯O and N—H⋯N hydrogen bonds and weak C—H⋯O inter­actions stabilize the crystal packing

Aqua­(4,4′-dimethyl-2,2′-bipyridine-κ2 N,N′)(nitrato-κO)(nitrato-κ2 O,O′)zinc

In the title compound, [Zn(NO3)2(C12H12N2)(H2O)], the ZnII atom is six-coordinated in a distorted octa­hedral geometry by two N atoms from a chelating 4,4′-dimethyl-2,2′-bipyridine ligand, one water O atom, one O atom from a monodentate nitrate anion and two O atoms from a chelating nitrate anion. In the crystal, there are aromatic π–π contacts between the pyridine rings [centroid–centroid distances = 3.9577 (13) Å] and inter­molecular O—H⋯O and C—H⋯O hydrogen bonds