Redox cycling and the toxicity of selenium compounds: A historical view

In 1816, Jöns Jakob Berzelius (Figure 5.1) and a group of five other individuals took over at auction an old distillery beside Gripsholm Castle near Mariefried that housed Sweden’s first chemical factories. It was in these factories that acetic and sulfuric acids were made in lead-lined chambers and produced to make white lead paint. Berzelius introduced the scientific analyses of products into the production methods of the factory. Sulfur was burned to produce sulfur dioxide, which, when combined with nitrogen dioxide and water, formed sulfuric acid. Alternatively, in place of elemental sulfur, iron pyrites could be burned to produce the sulfur dioxide. The lead-lined chambers contained the sulfuric acid and dissipated the heat from the synthetic exothermic reaction of sulfuric acid synthesis. In 1817, Berzelius isolated from the lead slimes what he thought was an arsenic compound from the iron pyrite process of making sulfur dioxide, and that process was discontinued. A red precipitate was discovered in the sulfur, which he first thought to be tellurium, but the starting materials for the synthesis of the sulfuric acid contained no detectable tellurium. The red element smelled of horseradish upon being burned. Berzelius must have soon realized that he had discovered a new element, and he named the element selenium (Se) for the Goddess of the moon, Selene. The new element was so named as its chemical properties were found to be similar to that of sulfur and that of tellurium named for the Earth, and selenium fit nicely just above tellurium and below sulfur in the Periodic Table. Element 34 was thus discovered, and the results of Berzelius’s discovery were published in 1817 (Berzelius, 1817).