Jan Hendrik de Boer (19 March 1899 – 25 April 1971) was a Dutch physicist and chemist.

De Boer was born in Ruinen, De Wolden, and died in The Hague.^[1] He studied at the University of Groningen and was later employed in industry.

Together with Anton Eduard van Arkel, de Boer developed a chemical transport reaction for titanium, zirconium, and hafnium known as the crystal bar process. In a closed vessel the metal reacts with iodine at elevated temperature forming the iodide. At a tungsten filament of 1700 °C the reverse reaction occurs, and the iodine and the metal are set free. The metal forms a solid coating at the tungsten filament and the iodine can react with additional metal, resulting in a steady turnover.^[2]

M + 2I₂ (>400 °C) → MI₄

MI₄ (1700 °C) → M + 2I₂

De Boer became a member of the Royal Netherlands Academy of Arts and Sciences in 1940, and foreign member in 1947.^[3]

• Metal–insulator transition
• Van Arkel–de Boer process