dicarbenium ions

https://doi.org/10.1351/goldbook.D01695
Species carrying two positive charges, formally located on tervalent carbon atoms, e.g. +CH2+CH2 ethane-1,2-diyl dication, +CH2CH2+CH2 propane-1,3-bis(ylium).
Source:
PAC, 1995, 67, 1307. (Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)) on page 1332 [Terms] [Paper]