Synthesis, Crystal Structure, and Thermal Properties of Metal-Containing Ionic Liquids with Spiro Cations: (Spiro)2MCl4 (Spiro = 2,8-Dioxo-5-azoniaspiro[4.5]decane or 2-Oxo-5-azoniaspiro[4.4]nonane, M = Mn, Ni, Co)

Metal-containing ionic liquids composed of the 2,8-dioxo-5-azoniaspiro[4.5]decane (MorphOx) and 2-oxo-5-azoniaspiro[4.4]nonane (PyrOx) spiro cations and tetrachlorometallate anions $${\text{MCl}}_{4}^{{2 - }}$$ (M = Mn, Ni, Co) were synthesized and studied by X-ray diffraction (CIF file CCDC nos. 2033482 (Morph-Ox2CoCl4), 2033483 (PyrOx2CoCl4), 2033484 (PyrOx2MnCl4), and 2033485 (PyrOx2NiCl4)). The compounds PyrOx2MCl4 are isostructural. The phase transition temperatures of the compounds were determined by differential scanning calorimetry.