Bismuth

Lustrous and silvery in appearance, bismuth is a rare element that has several quirky traits that combine to make it the least metal-like of all the metals.

As a pure metal, bismuth is brittle and has little use. Even so, its atypical nature is not all bad news. Under certain circumstances bismuth will behave like a semiconductor, for example in the thermoelectric material bismuth telluride. The semiconducting property of this compound means that it is used as a key component of many infrared detectors. 

John Emsley examines bismuth, following it's journey from discovery to tummy treatment, and explaining why its low melting point opens up os many possibilities for its use.