Jack David Dunitz FRS (29 March 1923 – 12 September 2021) was a British chemist and widely known chemical crystallographer.

[3] Dunitz's main research direction involved the use of crystal structure analysis as tool for studying chemical problems.

[5][6] With Leslie Orgel he also explained distortions of certain spinel minerals from cubic symmetry in terms of the Jahn-Teller effect.

[7] In his later research, at the ETH Zurich and after, Dunitz worked in several areas of structural chemistry, including the conformation and reactivity of medium-ring cycloalkanes and lactams,[8][9] ion-specificity of natural and synthetic ionophores,[10][11][12] chemical reaction paths (see Bürgi-Dunitz angle),[13][14][15] aspects of hydrogen bonding,[16][17][18] molecular motions in solids,[19][20][21][22] phase transformations and solid-state chemical reactions,[23][24] electron density distributions in crystals,[25][26] polymorphism,[27] and intermolecular interactions in condensed phases.

Dunitz wrote more than 380 scientific papers[49] and was the author of "X-Ray Analysis and the Structure of Organic Molecules" (Cornell University Press, 1979; Verlag Helvetica Chimica Acta, Basel, 1995), and "Reflections on Symmetry in Chemistry...and Elsewhere" (with Edgar Heilbronner, Verlag Helvetica Chimica Acta, Basel, 1993).