 Whereas the xenon fluorides are well @-@ characterized , the other halides are not known , the only exception being the <unk> , <unk> . Xenon <unk> is reported to be an <unk> , colorless , crystalline compound that <unk> into the elements at 80 ° C , formed by the high @-@ frequency irradiation of a mixture of xenon , fluorine , and silicon or carbon <unk> . However , doubt has been raised as to whether <unk> 
