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 anniversary can receive a message from the monarch for 60th, 65th, and 70th wedding anniversaries, and any wedding anniversary after that. This is done by applying to Buckingham Palace in the United Kingdom, or to the Governor-General's office in the other Commonwealth realms. In Australia, where one can receive a letter of congratulations from the Governor-General on the 50th and all subsequent wedding anniversaries; the Prime Minister, the federal Opposition leader, local members of both state and federal parliaments, and state Governors may also send salutations for the same anniversaries. In Canada, one can also receive a message from the Governor-General