Theory and experiment of the ESR of Co2+ in Zn2(OH)PO4 and Mg2(OH)AsO4

Abstract

Experiments of Electron Spin Resonance (ESR) were performed on Co 2+ substituting Zn 2+ or Mg 2+ in powder samples of Zn 2 (OH)PO 4 and Mg 2 (OH)AsO 4 . These two compounds are iso-structural and contain the Co 2+ in two environments of approximately octahedral and trigonal bipyramid structures. The observed resonances are described with a theoretical model that considers the departures from the two perfect structures. It is shown that the resonance in the penta-coordinated complex is allowed, and the crystal fields that would describe the resonance of the Co 2+ in the two environments are calculated. The small intensity of the resonance in the penta-coordinated complex is explained assuming that this site is much less populated than the octahedral one; this assumption was verified by a molecular calculation of the energies of the two environments, with both Co and Zn as central ions in Zn 2 (OH)PO 4 . 76.30.Fc,71.70.Ch,31.15.Ct

Stable Triarylmethyl Radicals and Cobalt(II) Ions Based 1D/2D Coordination Polymers

“…Broad ESR signals with g value at around 2.003 were observed in both CoCP ‐ 1 and CoCP ‐ 2 , in accordance with the presence of the open‐shell radical ligands (Figure 3b). In addition, an intense one‐line ESR signal was also found with g value around 4.25, which can be correlated to the paramagnetic Co(II) ion (Figure S8 and Tables S7, S10 in Supporting Information) [19] …”