The Tantalum Metals (1801-1866): Nineteenth-Century Analytical Chemistry and the Identification of Chemical Elements.

This paper examines the identification of chemical elements using mineral analysis, focusing on the controversy surrounding the "tantalum metals" between 1801 and 1866. Of these metals, only tantalum and niobium are still recognised as elements today; the discovery claims of columbium, pelopium, ilmenium and dianium were all retracted or refuted. Despite the theoretical and institutional changes that chemistry underwent during this time, the debates on the tantalum metals point towards a continuity in the identification of metals. For most of the nineteenth century, chemists continued to use the same types of analytical procedures as their mid-eighteenth-century predecessors. These analytical methods enabled the identification of metals based on the chemical behaviour of their compounds, without requiring their isolation in the form of simple substances (that is, as metals). Accordingly, the central questions in all of the debates on the tantalum metals were the correct identification of the properties of compounds and the elimination of impurities, rather than the simplicity of the new metals. The story of the tantalum metals therefore illustrates the fact that, despite the definition of chemical elements as simple substances, the discovery of new (metallic) elements only rarely coincided with the isolation of new simple substances.