With a theory developed by physicists in the 1920s called crystal field theory, scientists can explain why rubies and emeralds have the colors they do. Crystal field theory makes predictions about how ...

scientists can explain why rubies and emeralds have the colors they do. Crystal field theory makes predictions about how a transition metal ion's structure is affected by the other atoms ...

the current stream of research stems from studies conducted in the mid to late twentieth century of metalloproteins and metalloenzymes having transition metal ions at their active sites.