The title compound, [Li₂(C₁₈H₂₂BO)₂(C₆H₇N)₂], is a lithium dimesitylboroxide dimer in which the lithium cation is also coordinated by one mol­ecule of 2-methyl­pyridine. At the core of the structure is an Li₂O₂ four-membered ring. The structure is centrosymmetric with an inversion centre midway between two Li atoms. Inter­molecular C—Hπ inter­actions and π–π inter­actions between the 2-methyl­pyridine rings exist [centroid–centroid distance = 3.6312 (16) Å].

The title compound, C₃₆H₄₄B₂O·0.5CH₂Cl₂, contains an almost linear O—B—O linkage [177.23 (15)°] and approximately orthogonal [interplanar angles 89.49 (5) and 80.77 (4)°] trigonal planar B centers, consistent with the previously reported non-solvated structure [Cardinet al. (1983). J. Chem. Res. (S), p. 93]. Inter­molecular C—Hπ inter­actions exist between mesityl groups, with a C—Hcentroid separation of 3.6535 (18) Å. The dichloromethane mol­ecules lie on twofold rotation axes.

The title compound, C₉H₇IN⁺·Cl⁻·2H₂O, was obtained during the synthesis of 8-iodo­quinoline from 8-amino­quinoline using the Sandmeyer reaction. The 8-iodo­quinolinium ion is almost planar. Solvent water mol­ecules and chloride ions form a hydrogen-bonded chain along the c axis via O—HCl links. The 8-iodo­quinolinium ions, which are packed along the c axis with cationic aromatic π–π stacking (centroid–centroid distance = 3.624 Å), are linked to the chain via N—HO hydrogen bonds.

The title compound, C₉H₇IN⁺·I₃⁻·C₄H₈O, was synthesized from 8-amino­quinoline using the Sandmeyer reaction. The 8-iodo­quinolinium cation is essentially planar and the triiodide ion is almost linear. N—HO hydrogen bonds, and inter­molecular II [3.7100 (5) Å] and IH inter­actions, between the cation, anion and solvent mol­ecules result in the formation of sheets oriented parallel to the (03) plane. Between the sheets, 8-iodo­quinolinium and triiodide ions are stacked alternately, with IC distances in the range ∼3.8–4.0 Å.