A triclinic polymorph of 3-nitro­anilinium chloride

The asymmetric unit of the title compound, C6H7N2O2 +·Cl−, contains two independent ion pairs. A monoclinic form of the title compound with only one ion pair in the asymmetric unit has been reported previously [Ploug-Sørensen & Andersen (1986). Acta Cryst. C42, 1813–1815]. In the crystal of the title compound, the components are linked into layers parallel to (001) by inter­molecular N—H⋯Cl hydrogen bonds, with alternating hydro­philic and hydro­phobic regions

Creatininium hydrogen maleate

In the title compound, C4H8N3O+·C4H3O4 −, the cations and anions are linked through N—H⋯O hydrogen bonds making a ionic pair with an R 2 2(8) ring motif. These ionic pairs are further connected through another N—H⋯O hydrogen bond, leading to an R 6 6(16) ring motif around the inversion centres of the unit cell. These approximately planar aggregates are further connected through weak van der Waals inter­actions in the unit cell. The anions have a characteristic intra­molecular O—H⋯O hydrogen bond with a self-associated ring S(7) motif

1,5-Dimethyl-3-oxo-2-phenyl-2,3-di­hy­dro-1H-pyrazol-4-aminium 2-hydroxy­benzoate

In the title salt, C11H14N3O+·C7H5O3 −, the phenyl ring of the cation is oriented at an angle of 67.0 (1)° with respect to the five-membered pyrazolone ring. The carboxyl­ate plane of the anion is twisted out from the plane of the aromatic ring at an angle of 13.7 (3)°. In the crystal, the cations form hydrogen-bonded dimers with an R 2 2(10) ring motif. The salicylate anion has an intra­molecular O—H⋯O hydrogen bond

Creatininium cinnamate

The crystal structure of the title compound (systematic name: 2-amino-1-methyl-4-oxo-4,5-dihydro-1H-imidazol-3-ium 3-phenyl­prop-2-enoate), C4H8N3O+·C9H7O2 −, is stabilized by N—H⋯O hydrogen bonding. Cations are linked to anions to form ion pairs with an R 2 2(8) ring motif. These ion pairs are connected through a C 2 2(6) chain motif extending along the c axis of the unit cell. This crystal packing is characterized by hydro­phobic layers at x ∼ 1/2 packed between hydro­philic layers at x ∼ 0

Creatinium hydrogen oxalate

The crystal structure of the title compound, C4H10N3O2 +·C2HO4 −, is stabilized by N—H⋯O and O—H⋯O hydrogen bonds. The anions are connected by an O—H⋯O hydrogen bond, leading to C(5) chain extending along c axis. The cations are dimerized around the corners of the unit cell, leading to an R 2 2(14) ring motif. This leads to a cationic mol­ecular aggregation at x = 0 or 1 and an anionic mol­ecular aggregation at x = 1/2

Creatininium 2-chloro­acetate

In the title compound (systematic name: 2-amino-1-methyl-4-oxo-4,5-dihydro-1H-imidazol-3-ium 2-chloro­acetate), C4H8N3O+·C2H2ClO2 −, the mol­ecular aggregations are stabil­ized through classical (N—H⋯O) and non-classical (C—H⋯O and C—H⋯N) hydrogen-bonding inter­actions. The cations are linked to the anions, forming ion pairs through two N—H⋯O bonds that produce characteristic R 2 2(8) ring motifs. These cation–anion pairs are connected through another N—H⋯O hydrogen bond, leading to an R 4 2(8) ring motif. Further weak C—H⋯N inter­actions link the mol­ecules along the a axis, while other C—H⋯O inter­actions generate zigzag chains extending along b

(E)-3-Phenyl-3-(3-phenyl-1H-1-pyrazol­yl)-2-propenal

In the title compound C18H14N2O, the pendant rings make dihedral angles of 66.1 (1)° and 13.9 (1) with the central ring. In the crystal, two mol­ecules form a cyclic centrosymmetric R 2 2(22) dimer through pairs of C—H⋯O bonds. These dimers are further connected into zigzag chains extending along the b axis through C—H⋯π and C—H⋯O inter­actions

2-Amino-6-(2,4-dichloro­phen­yl)-4-oxo-3,5-diphenyl­cyclo­hex-2-enecarbonitrile

In the title compound, C25H18Cl2N2O, the cyclo­hexene ring has a sofa conformation. All the substituents in the cyclo­hexene ring, except the cyano group (which is axial) occupy equatorial positions. The crystal structure is stabilized through N—H⋯O hydrogen bonds, forming a chain extending along the b axis and through C—H⋯N and C—H⋯Cl inter­actions. It is remarkable that only one of the amino H atoms is involved in hydrogen bonding

2,6-Bis(2-chloro­phen­yl)-4-oxo-3,5-diphenyl­heptane-1,1,7,7-tetra­carbo­nitrile

In the title compound, C35H24Cl2N4O, the phenyl rings are oriented almost parallel to each other, making a dihedral angle of 0.6 (2)°, whereas the chloro­phenyl rings are oriented at a dihedral angle of 28.3 (1)°. The crystal structure is stabilized through an extensive series of C—H⋯N, C—H⋯O and C—H⋯Cl inter­actions. One of the C—H⋯N inter­actions generates an R 2 2(12) ring motif around a crystallographic inversion centre. C(5), C(10) and C(12) chain motifs are observed in the unit cell through C—H⋯N and C—H⋯Cl inter­actions. During the structure analysis, it was observed that the unit cell contains large accessible voids, which host disordered solvent mol­ecules. This affects the diffraction pattern, mostly at low scattering angles and was corrected with the SQUEEZE program [Spek, A. L. (2009 ▶). Acta Cryst. D65, 148–155]

4-Chloro­anilinium 3-carb­oxy­prop-2-enoate

In the title compound, C6H7ClN+·C4H3O4 −, the cations and anions lie on mirror planes and hence only half of the mol­ecules are present in the asymmeric unit. The 4-chloro­anilinium cation and hydrogen maleate anion in the asymmetric unit are each planar and are oriented at an angle of 15.6 (1)° to one another and perpendicular to the b axis. A characterestic intra­molecular O—H⋯O hydrogen bond, forming an S(7) motif, is observed in the maleate anion. In the crystal, the cations and anions are linked by N—H⋯O hydrogen bonds, forming layers in the ab plane. The aromatic rings of the cations are sandwiched between hydrogen-bonded chains and rings formed through the amine group of the cation and maleate anions, leading to alternate hydro­phobic (z = 0 or 1) and hydro­philic layers (z = 1/2) along the c axis