Re-investigation of the infrared spectrum of the NCN radical by laser magnetic resonance spectroscopy

•Reinvestigation of the NCN free radical in its 3Σg- ground electronic state.•Specially designed Helmholtz coils led to increased sensitivity.•Over one hundred new absorption lines of NCN observed by laser magnetic resonance.•Improved set of molecular parameters in the 301 fundamental and 211301 hot band of NCN.•Molecular parameters determined using LMR and Fourier Transform spectra.•Magnetic fields for over 50 observed transitions, not attributed to NCN, are given.