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
Marriage and wedding customs in the Philippines the coin bearer acts as the holder and keeper of the arrhae until it is offered and given by the groom to his bride. Among the secondary sponsors or wedding attendants, three pairs – each pair consists of a male and a female secondary sponsor – are chosen to light the wedding candles, handle the veils, and place the cord. After the exchange of wedding rings by the couple, the groom gives the wedding arrhae to his bride. The arrhae is a symbol of his "monetary gift" to the bride because it is composed of 13 pieces of gold, or