Russell and Sigurd Varian developed the first Klystron tube in the US.
Linus Pauling publishes The Nature of the Chemical Bond, a compilation of a decades worth of work on chemical bonding. It is one of the most important modern chemical texts. It explains hybridization theory, covalent bonding and ionic bonding as explained through electronegativity, and resonance as a means to explain, among other things, the structure of benzene
Magnetic Moment of Neutron, Alvarez
Discovery of Francium (Marguerite Catherine Perey)
Nuclear Fission Theory, O. Frisch and L. Meitner
Vitamin K Synthesis
19 September 1939 discovery of 2638 Gadolin
7 November 1939 Death of Ralph Allen Sampson in Bath, England
1939 Death of Sören Sörensen
Physics to Ernest Orlando Lawrence "for the invention and development of the cyclotron and for results obtained with it, especially with regard to artificial radioactive elements"
Physiology or Medicine to Gerhard Domagk "for the discovery of the antibacterial effects of prontosil"