Iodobenzene is best prepared using this procedure.
http://www.orgsyn.org/orgsyn/prep.asp?prep=cv2p0351 (http://www.orgsyn.org/orgsyn/prep.asp?prep=cv2p0351)
The preparation of iodobenzene by iodination of benzene, with iodine and nitric acid: Org. Syn. Coll. Vol. I, 1941, 323.