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
SN 1054 are not confirmed so conclusively: supernovas of the first millennium (SN 185, SN 386 and SN 393) are established on the basis of a single document each, and so they cannot be confirmed; in relation to the supposed historical supernova which followed the one in 1054, SN 1181, there are legitimate doubts concerning the proposed remnant (3C58) and an object of less than 1000 years of age. Other historical supernovae of which there are written accounts which precede the invention of the telescope (SN 1006, SN 1572 and SN 1604) are however established with certitude. Telescope-era supernovae are of course