Ryutaro Tsuchida (槌田·龍太郎; 1903-1962) was a Japanese chemist. Tsuchida graduated from

Tokyo University The University of Tokyo (, abbreviated as in Japanese and UTokyo in English) is a public research university in Bunkyō, Tokyo, Japan. Founded in 1877 as the nation's first modern university by the merger of several pre-westernisation era ins ...

in (昭和3年，

Shōwa era The was a historical period of History of Japan, Japanese history corresponding to the reign of Emperor Shōwa (Hirohito) from December 25, 1926, until Death and state funeral of Hirohito, his death on January 7, 1989. It was preceded by the T ...

3rd) 1928. In June 1935, he established a fifth course at

Osaka University The , abbreviated as UOsaka or , is a List of national universities in Japan, national research university in Osaka, Japan. The university traces its roots back to Edo period, Edo-era institutions Tekijuku (1838) and Kaitokudō, Kaitokudo (1724), ...

. In 1939, he originally proposed the correlation between

molecular geometry Molecular geometry is the three-dimensional arrangement of the atoms that constitute a molecule. It includes the general shape of the molecule as well as bond lengths, bond angles, torsional angles and any other geometrical parameters that det ...

and number of

valence electron In chemistry and physics, valence electrons are electrons in the outermost shell of an atom, and that can participate in the formation of a chemical bond if the outermost shell is not closed. In a single covalent bond, a shared pair forms with b ...

pairs (both shared and unshared pairs). This concept was later developed into the

VSEPR theory Valence shell electron pair repulsion (VSEPR) theory ( , ) is a conceptual model, model used in chemistry to predict the geometry of individual molecules from the number of electron pairs surrounding their central atoms. It is also named the Gill ...

of molecular geometry.

References

1903 births 1962 deaths 20th-century Japanese chemists Scientists from Kyoto {{chemist-stub