From the reactions of ethane-1,2-dioyl dichloride

Ethane-1,2-dioyl dichloride oxalyl chloride (COCOj) reacts with antimony(V) fluoride above -35 C to form COCIF (identified by in situ infrared analysis) and SbFj. The reaction was accompanied by the generation of a small quantity of CO, and possibly COFj. Examination of the infrared spectrum during the progress of the reaction when cooled to -50 C revealed the formation of an intermediate oxocarbonium salt. The reaction was interpreted in the following terms [7]  

The initially formed dication [(CO)2]2 is stable below -50 C, but decomposes with cleavage of the carbon-carbon bond into the radical ions [CO] , and COCIF is formed via a redox reaction with the associated anion. 

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