Arsenobenzene reacts with CF3I to give C6H5As(CF3)2, C6H5As(CF3)I, and C6H5AsI2. C6H5As(CF3)I and AgCl yield C6H5As(CF3)Cl. The compounds CF2=CFX react with (CH3)2As—As(CH3)2 under mild conditions to give 1:1 adducts (CH3)As—CF2CFX—As(CH3)2 (X = CF3, Br). Some (CH3)2As—CF=CF2 is produced when X = Br and is the major product when X = I. When X = F a 1:4 adduct (CH3)2As—(CF2CF2)4—As(CH3)2 is probably formed on ultraviolet irradiation. (CH3)2As—As(CH3)2 reacts with CF3C≡CCF3 to give cis and trans (CH3)2AsC(CF3)=C(CF3)As(CH3)2 and with [Formula: see text] to give (CH3)2AsF and [Formula: see text].