Continuous-wave (CW) X-band (9.38 GHz) EPR spectra of liquid solutions of [1 •-]([X + ]) were collected on a Bruker EMX Plus EPR spectrometer with 0.6 T electromagnet. The samples were prepared inside the glovebox and transferred into a quartz EPR tube (4 mm outer diameter). For each sample, we performed a two-dimensional measurement of signal intensity against microwave power to ensure we are in the non-saturating regime. Fitting and simulation of the recorded EPR spectra were performed using the Xepr Bruker software, assuming a model spin Hamiltonian that consists of a sum of electron-Zeeman and electron-nuclei hyperfine interactions: