Period 5 element with most production coming from the Xikuangshan Mine in Hunan. Antimony compounds are prominent additives for chlorine and bromine containing fire retardants found in many commercial and domestic products. The largest application for metallic antimony is as alloying material for lead and tin. It improves the properties of the alloys which are used as in solders, bullets and ball bearings. An emerging application is the use of antimony in microelectronics. Tellurium is a chemical element that has the symbol Te and atomic number 52. A brittle, mildly toxic, rare, silver-white metalloid which looks similar to tin, tellurium is chemically related
Porous silicon Porous silicon Porous silicon (abbreviated as "PS" or "pSi") is a form of the chemical element silicon that has introduced nanopores in its microstructure, rendering a large surface to volume ratio in the order of 500 m/cm. Porous silicon was discovered by accident in 1956 by Arthur Uhlir Jr. and Ingeborg Uhlir at the Bell Labs in the U.S. At the time, the Ulhirs were in the process of developing a technique for polishing and shaping the surfaces of silicon and germanium. However, it was found that under several conditions a crude product in the form of thick black, red