Crystal structures of potassium tri­fluorido­(4-meth­oxy­phen­yl)borate and potassium tri­fluorido(4-fluoro­phen­yl)borate

Despite their different compositions and space groups, the irregular KF₈ coordination polyhedra of the potassium cations in these structures are almost identical. The layer stacking sequences are AAA... in the p-methoxy compound and ABAB... in the p-fluoro compound.

2-[(E)-2-(3,4-Di­chloro­benzyl­idene)hydrazin-1-yl]quinoxaline

The 21 non-H atoms of the title compound, C₁₅H₁₀Cl₂N₄, are almost planar (r.m.s. deviation = 0.032 Å); the conformation about the N=C bond [1.277 (6) Å] is E. In the crystal, zigzag supra­molecular chains along the c axis (glide symmetry) are formed via N—H...N hydrogen bonds. These associate along the b axis by π–π inter­actions between the fused and terminal benzene rings [inter­centroid distance = 3.602 (3) Å] so that layers form in the bc plane.

2-(2-Amino-4-nitro­phen­yl)-7-nitro-4H-3,1-benzoxazin-4-one

In the title compound, C₁₄H₈N₄O₆, the benzoxazin-4-one fused-ring system (r.m.s. deviation = 0.018 Å) is coplanar with the attached benzene ring [dihedral angle = 0.81 (4)°], there being an intra­molecular N—H...N hydrogen bond between them. Each nitro group is twisted out of the plane of the attached benzene ring [O—N—C—C torsion angles = 167.94 (11) and 170.38 (11)°]. In the crystal, amine–nitro N—H...O hydrogen bonds lead to centrosymmetric dimeric aggregates that are connected into a three-dimensional architecture by oxazin­yl–nitro C—H...O and π–π inter­actions [inter-centroid distance between the oxazinyl and terminal benzene rings = 3.5069 (7) Å].

7-Chloro-4-(2-hy­droxy­ethyl­amino)­quinolin-1-ium chloride

In the title salt, C₁₁H₁₂ClN₂O⁺·Cl⁻, the ten non-H atoms comprising the quinolinium residue are coplanar (r.m.s. deviation = 0.041 Å) and the hy­droxy­ethyl group is approximately perpendicular to this plane [C_ring—N—C_methyl­ene—C torsion angle = −74.61 (18)°]. A supra­molecular chain aligned along [101] mediated by charge-assisted O/N—H...Cl⁻ hydrogen bonds features in the crystal packing. Chains are connected into a three-dimensional architecture by C—H...O(hy­droxy) inter­actions.