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 Wedding A wedding is a ceremony where two people are united in marriage. Wedding traditions and customs vary greatly between cultures, ethnic groups, religions, countries, and social classes. Most wedding ceremonies involve an exchange of marriage vows by the couple, presentation of a gift (offering, rings, symbolic item, flowers, money), and a public proclamation of marriage by an authority figure or celebrant. Special wedding garments are often worn, and the ceremony is sometimes followed by a wedding reception. Music, poetry, prayers or readings from religious texts or literature are also commonly incorporated into the ceremony, as well as superstitious customs