“…These crystalline water-based solids are thought to be ubiquitous on earth, especially on the ocean floor and within the surface layer of the permafrost regions. It is conservatively estimated that the energy thought to be contained in natural CHs is double that of currently recoverable worldwide fossil fuels. , Beyond on earth, CHs were also identified on comets, Mars, and other outer planets. − Thus, CHs are viewed as a potential energy resource for the future, such as future clean energy resource , and gas transportation. , To date, a large number of the guest molecules (CO 2 , CH 4 , CO, H 2 , and N 2 ) encaging CHs have been investigated in order to explore their structures and inherent nature of inclusion phenomena. − A particular type of CHs in this category is the magnetic ones, which contain free radicals, high-spin substances, or excess electrons in their stacked nanocages, exhibiting unusual and discrete magnetic phenomena. − Molecular oxygen, O 2 , is the simplest magnetic molecule with a spin S = 1 in its ground state, and its magnetism in the confined states absorbed in one-dimensional channel and two-dimensional layer structures or in solid state was investigated. − It should be noted that several O 2 CHs (O 2 @CHs) were prepared with experimental characterization of structures and properties, ,− revealing the possibility of preparing O 2 @CHs with target structures and properties. However, information about the structures and properties of such magnetism-suspected CHs, especially the associated magnetic properties, are quite scarce.…”