P. Kazmierczak et al., Oxidative chlorination of various iodoarenes to (dichloroiodo)arenes with chromium(VI) oxide as the oxidant, J CHEM R-S, (1), 1999, pp. 64-65
Chromium(vl) oxide dissolved in a mixture of acetic acid with concentrated
hydrochloric acid converts, at or near room temperature. iodoarenes to (dic
hloroiodo)arenes, in a very simple and efficient procedure.