Crystal structure "white tin" respectively. Two more allotropes, γ and σ, exist at temperatures above 161 °C and pressures above several GPa. White tin is metallic, and is the stable crystalline form at or above room temperature. Below 13.2 °C, tin exists in the gray form, which has a diamond cubic crystal structure, similar to diamond, silicon or germanium. Gray tin has no metallic properties at all, is a dull gray powdery material, and has few uses, other than a few specialized semiconductor applications. Although the α–β transformation temperature of tin is nominally 13.2 °C, impurities (e.g. Al, Zn, etc.) lower the
The Anniversary (Fawlty Towers) The Anniversary (Fawlty Towers) "The Anniversary" is the fifth episode of the second series of BBC sitcom "Fawlty Towers". As in other episodes, the letters of the sign for Fawlty Towers are shown rearranged in the opening sequence. In this episode, it says "Flowery Twats". The use of the obscene word has caused this to be given a 12 certificate by the BBFC, which is the only episode in the series to have a more restrictive rating than PG. On the morning of their wedding anniversary, Sybil recalls how Basil forgot last year. Basil has secretly invited their closest friends