Sn – tin – is a soft, malleable, ductile, silvery-white metal. When a piece of tin is bent, it makes a screaming sound called a "tin cry" due to breakage in its crystal structure. Tin is combined with other elements to form a wide variety of commercially significant alloys, such as soft solder, pewter, bronze, and phosphor bronze. Other metals are often plated with tin to prevent corrosion. Tin itself, however, is susceptible to a “disease” known as tin pest, which refers to the element changing allotropes from its silvery metallic form to its brittle grey form. This can cause problems if the metal is intended for use at temperatures below 13.2oC. Tin pest even has historical significance. In 1910 British polar explorer Robert Scott hoped to reach the South Pole, but he and his team were supposedly left without kerosene when it leaked from tin-sealed cans affected by tin pest.