Chemistry
Crystal Field Theory Basics
Quick fact
The color of many transition metal complexes, such as the ruby red of chromium in corundum, comes from the absorption of specific wavelengths of light that cause electrons to jump between split d-orbitals.
Why this is interesting
You've probably seen vivid colors in gemstones or solutions, like the deep blue of a copper complex. But why do these seemingly simple compounds display such a rainbow of hues?