 In the heads of some safety matches , antimony ( III ) sulfide is used . Antimony @-@ 124 is used together with beryllium in neutron sources ; the gamma rays emitted by antimony @-@ 124 initiate the <unk> of beryllium . The emitted neutrons have an average energy of 24 keV . Antimony sulfides have been shown to help stabilize the friction coefficient in automotive brake pad materials . 
