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
San Tin the area. The Man clan decided to settle in the area in the 15th century. They dried the marshes and gradually filled them with soil, turning them into 800 hectare of rice paddies. This is reflected by the name San Tin, which means "new field"s. The San Tin areas are divided into nine villages within the area most notable areas are Wing Ping Tsuen (), which is close to the Tai Fu Tai Mansion, and Fan Tin Tsuen (). The areas around San Tin are covered in wetlands hence their main products are cabbages (like Chinese cabbage or kai-lan) and