Tin bent, a crackling sound known as the "tin cry" can be heard from the twinning of the crystals. Tin melts at low temperatures of about , the lowest in group 14. The melting point is further lowered to for 11 nm particles. β-tin (the metallic form, or white tin, BCT structure), which is stable at and above room temperature, is malleable. In contrast, α-tin (nonmetallic form, or gray tin), which is stable below , is brittle. α-tin has a diamond cubic crystal structure, similar to diamond, silicon or germanium. α-tin has no metallic properties at all because its atoms form
Gift white elephant. One means of reducing the mismatch between the buyer and receivers' tastes is advance coordination, often undertaken in the form of a wedding registry or Christmas list. Wedding registries in particular are often kept at a single store, which can designate the exact items to be purchased (resulting in matching housewares), and to coordinate purchases so the same gift is not purchased by different guests. One study found that wedding guests who departed from the registry typically did so because they wished to signal a closer relationship to the couple by personalizing a gift, and also found that