Depends where you live. The article is on bbc.co.uk and Aluminium is the usual spelling used in the UK. From Wikipedia: "Two variants of the metal's name are

Depends where you live. The article is on bbc.co.uk and Aluminium is the usual spelling used in the UK. From Wikipedia: "Two variants of the metal's name are in current use, aluminium and aluminum (besides the obsolete alumium). The International Union of Pure and Applied Chemistry (IUPAC) adopted aluminium as the standard international name for the element in 1990 but, three years later, recognized aluminum as an acceptable variant. Hence their periodic table includes both. IUPAC prefers the use of aluminium in its internal publications, although nearly as many IUPAC publications use the spelling aluminum. Most countries use the spelling aluminium. In the United States and Canada, the spelling aluminum predominates. The Canadian Oxford Dictionary prefers aluminum, whereas the Australian Macquarie Dictionary prefers aluminium. In 1926, the American Chemical Society officially decided to use aluminum in its publications; American dictionaries typically label the spelling aluminium as "chiefly British"." [1] [1] http://en.wikipedia.org/wiki/Aluminium#Etymology http://en.wikipedia.org/wiki/Aluminium#Etymology