The first international scientific conference took place in Karlsruhe on September 3, 1860 to promote chemistry across the world. Chemists discussed on the atomic weight of oxygen and carbon. Jöns Jacob Berzelius, a Swedish chemist stated that electrostatic forces were important for ionic bonding in salt, but then he had incorrectly concluded that all molecular bonding was originated by electrostatic attraction. Berzelius mentioned that diatomic molecules such as H2 and O2 were impossible because the atoms would repel each other. Kekuĺ, a young German chemist, discussed on the valency of the carbon. Several topics were covered in the conference that includes stoichiometry or representation of molecular formulas.