organic compounds
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The two-dimensional crystal packing of the title compound, C3H5N4O2+·NO2−·H2O, results from the stacking of well separated layers (i.e. with nothing between the layers) parallel to the (-113) plane in which adjacent cations adopt a head-to-head arrangement such that two –COOH groups are linked via two water molecules (the water O atom behaves simultaneously as donor and acceptor of hydrogen bonds) and two –NH2 groups are linked through two nitrate anions. This arrangement leads to alternating hydrophilic and hydrophobic zones in which O—HO and N—HO hydrogen bonds, respectively, are observed.
organic compounds
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In the title compound, 2C3H5N4O2+·H2PO4-·NO3-·C3H4N4O2, three independent 5-amino-1H-1,2,4-triazol-3-carboxylic acid moieties are observed. Two are in the form of cations, while the third is in the zwitterionic form. The triazole rings in the two cations are almost coplanar, making an angle of 4.11 (7)°. Layers parallel to the (20-1) plane, resulting from hydrogen bonding of the organic molecules and the nitrate anions, are linked via H2PO4- infinite zigzag chains running parallel to the c axis. The crystal studied was an inversion twin, with refined components of 0.33 (7) and 0.67 (7).
organic compounds
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The asymmetric unit of the title compound, C6H7N2O2+·Cl−·0.5H2O, consists of two protonated 2-amino-3-carboxypyridine cations, two chloride anions and one molecule of water. The crystal packing can be described as alternating layers of cations and anions parallel to (110), which are linked together by Ow—HCl interactions. In the crystal, four types of classical hydrogen bonds are observed, viz. cation–anion (O—HCl and N—HCl), cation–cation (N—HO), cation–water (N—HOw) and water–anion (Ow—HCl), resulting in the formation of an infinite three-dimensional network.
organic compounds
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The asymmetric unit includes two crystallographically independent equivalents of the title salt, C6H7N2O2+·ClO4−. The cations and anions form separate layers alternating along the c axis, which are linked by N—HO, O—HO and C—HO hydrogen bonds into a two-dimensional network parallel to (100). Further C—HO contacts connect these layers, forming a three-dimensional network, in which R44(20) rings and C22(11) infinite chains can be identified.
organic compounds
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The asymmetric unit of the title compound, C5H6N3O2+·ClO4−·2C5H5N3O2·H2O, comprises two symmetry-independent zwitterions, one cation, one perchlorate anion and one water molecule. In the crystal, the three different types of organic entities are linked by N—HO and N—HN hydrogen bonds, forming undulating sheets parallel to (1-10). These sheets are in turn connected by O—HN and O—HO hydrogen bonds involving perchlorate anions and water molecules, forming a three-dimensional network. Intramolecular N—HO and weak intermolecular C—HO hydrogen bonds are also present.