Antimony (Sb) is a chemical element with atomic number (Z) 51, group 15, period 5, and atomic weight 121.760. The Antimony (Sb) is a semi-metallic chemical element: the metallic form is bright, silvery, hard and brittle; the non metallic form is a grey powder, used to make certain types of semiconductor devices, such as diodes and infrared detectors. (Refer to the Chemical Element; Periodic Table)