Elemental silicon was prepared for the first time by Berzelius, in 1823, who placed silicon tetrafluoride in the presence of warm potassium. However, it was thought that Gay-Lussac and Thenard had already tried to obtain the amorphous silicon by the same method, in 1809. The substance obtained by Berzelius was a purer product as a result of exhausting filtering. Berzelius prepared silicon from the reaction of potassium fluorsilicates with potassium.