The photolysis of iron(III) chloride in chloroform
In air-saturated solutions, iron(III) chloride functions as a long wavelength sensitizer of the photolysis of chloroform. In the presence of oxygen, irradiation of chloroform solutions of iron(III) chloride at wavelengths above 340 nm leads to the formation of HFeCl4, followed by continued production of HCl and C2Cl6 as chlorine photodissociates from HFeCl4, while the Fe(II) species formed is reoxidized. When iron(III) chloride is photolyzed in the absence of oxygen, conversion to HFeCl4 and reduction to colloidal FeCl2 occur simultaneously, ending in complete reduction. Both CCl3OO and CCl3OOH appear to participate in the reoxidation of iron(II) chloride.
Patrick E. Hoggard, Michael Gruber, and Arnd Vogler, "The photolysis of iron(III) chloride in chloroform", Inorg. Chim. Acta 346, 137-142 (2003).