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
Bengali Muslim wedding traditional wedding is arranged by Ghotoks (matchmakers), who are generally friends or relatives of the couple, or sometimes just professional matchmakers. The Ghotoks facilitate the couple's introduction to the wedding guests, and are given special gifts called "Ghotokbidae" (lit., "bidding goodbye to the Ghotoks") if the alliance is agreed upon and the marriage is realized. Families traditionally seek their children's matches from the same caste, religion and social standing. In the case of an arranged marriage, if the aforementioned 'compatibility' factors are duly matched, only then is the pairing deemed a raj-jotak (an ideal match). Nowadays (as arranged marriages are