Tin pest related problems such as tin whiskers. At 13.2 °C (about 56 °F) and below, pure tin transforms from the silvery, ductile metallic allotrope of β-form "white tin" to the brittle, nonmetallic, α-form "grey tin" with a diamond cubic structure. The transformation is slow to initiate due to a high activation energy but the presence of germanium (or crystal structures of similar form and size) or very low temperatures of roughly −30 °C aids the initiation. There is also a large volume increase of about 27% associated with the phase change to the nonmetallic low temperature allotrope. This frequently makes tin
Wedding customs by country weddings in the United States follow a similar pattern to an English wedding. It traditionally follows the "white wedding" type (see also "Wedding types" below), which originates from the white color of the bride's wedding dress, but refers to an entire wedding routine. Customs and traditions vary, but common components are listed below. The purpose of inviting guests is to have them witness a couple's marriage ceremony and vows and to share in their joy and celebration. Gifts for the wedding couple are optional, although most guests attempt to give at least a token gift of their best wishes. Some