Skip to content
Fellows Directory

James McConnell

Professor James McConnell FRS


Elected: 1987


James McConnell brings ideas and techniques from modern solid-state physics and chemistry to bear on a broad range of mineral transformation behaviours. He has furthered our understanding of ordering transformations in minerals — particularly the origin of incommensurate (IC) modulated structures — by applying group theory and symmetry principles generally.

James’ pioneering application of electron microscopy to mineralogy led to the first identification of antiphase structure, spinodal behaviour and other effects in feldspars, sulphides, pyroxenes and oxides. His early work showed how kinetics gave evidence of the transformation mechanism. His thermodynamic studies showed that IC modulated structures are nearly as well ordered as the pure end-member structures. At Schlumberger Cambridge Research, he elucidated various properties of shales.

Upon taking up a chair in the physics and chemistry of minerals at Oxford, he focused on the simulation of mineral structures in relation to the thermodynamics of components of IC phases, receiving a Humboldt Research Award for this work. His group theoretical study of order–disorder transitions provided the first viable model for three-dimensional ordering.

Professional positions

Emeritus Professor of Physics and Chemistry of Minerals, University of Oxford
Honorary Fellowship, St Hugh's College, Oxford, University of Oxford

Interests and expertise

Subject groups


incommensurate structures, order-disorder behaviour