Introduction

Abstract

The initial recorded discovery of selenium is attributed [1] to two Swedish chemists J. J. Berzelius and J. G. Gahn who observed a curious residual slime during the oxidation of sulfur dioxide from copper pyrites. It is also possible that selenium was discovered earlier: in the “Rosarius Philosophorum” of Arnold of Villanova, written in the fourteenth century, there is reference to a red sulfur deposit (sulfur rubeum) which formed on the walls of the oven after the condensation of crude sulfur.