Antimony discontinued. Antimony is resistant to attack by acids. Four allotropes of antimony are known: a stable metallic form and three metastable forms (explosive, black and yellow). Elemental antimony is a brittle, silver-white shiny metalloid. When slowly cooled, molten antimony crystallizes in a trigonal cell, isomorphic with the gray allotrope of arsenic. A rare explosive form of antimony can be formed from the electrolysis of antimony trichloride. When scratched with a sharp implement, an exothermic reaction occurs and white fumes are given off as metallic antimony forms; when rubbed with a pestle in a mortar, a strong detonation occurs. Black antimony
Silicon-germanium silicon-only technology. Silicon Germanium-on-insulator (SGOI) is a technology analogous to the Silicon-On-Insulator (SOI) technology currently employed in computer chips. SGOI increases the speed of the transistors inside microchips by straining the crystal lattice under the MOS transistor gate, resulting in improved electron mobility and higher drive currents. SiGe MOSFETs can also provide lower junction leakage due to the lower band gap value of SiGe. However, a major issue with SGOI MOSFETs is the inability to form stable oxides with silicon germanium using standard silicon oxidation processing. A silicon germanium thermoelectric device, MHW-RTG3, was used in the Voyager 1 and 2