ANi(AsF6)3 (A = H3O+, O2+, NO+, NH4+ and K+) compounds are structurally related to previously known H3OCo(AsF6)3. The main features of the structure of these compounds are rings of NiF6 octahedra sharing apexes with AsF6 octahedra connected into infinite tri-dimensional network. In this arrangement cavities are formed where single charged cations are placed.
In O2Ni(AsF6)3 the vibrational band belonging to O2+ vibration is found at 1866 cm−1, which is according to the literature data one of the highest known values, and it is only 10 cm−1 lower than the value for free O2+.