👉 Chromotropy is a concept in nuclear magnetic resonance (NMR) spectroscopy that describes how the spin of an electron changes when it interacts with another electron. In NMR, electrons are orbitals and they can be split into two types depending on their quantum numbers: spin 1/2 (S1/2) or spin 1/3 (S1/3). The strength of these interactions depends on the distance between the nuclei involved. When an electron in one nucleus is