Johan Gadolin was a famous Finnish chemist, physicist and a mineralogist. He is most well known for discovering the element yttrium. Yttrium was the first "rare earth element" discovered. He also showed how elements can show several oxidation states.
Example: 2 Sn(II)
is in equilibrium with
Sn(0) + Sn(IV).
Gadolin also studied specific heats and latent heats in 1787–92. This thermochemical work was very precise. He later became a professor at the Royal academy of Turuk. Gadolin wrote the first anti-phlogiston chemistry textbook in the Nordic countries.
Example: 2 Sn(II)
Gadolin also studied specific heats and latent heats in 1787–92. This thermochemical work was very precise. He later became a professor at the Royal academy of Turuk. Gadolin wrote the first anti-phlogiston chemistry textbook in the Nordic countries.
http://en.wikipedia.org/wiki/Johan_Gadolin