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
Wedding reception of a couple's entire wedding budget is spent on the reception alone. This is primarily due to the cost of food and alcohol. Wedding traditions vary between countries, and between regions of the same country. Some traditions include: Unless the wedding couple has a wedding registry, it is best not to give gifts or gift certificates. For Chinese weddings, cash or a cheque is always the best gift. In addition to that, some elder relatives might also give gold jewelry. The cash or cheque should be in a red envelope or red pocket with the givers' names on it, and