The spin-only magnetic moment value of \( \mathrm{M^{3+}} \) ion (in gaseous state) from the pairs \( \mathrm{Cr^{3+}/Cr^{2+}} \), \( \mathrm{Mn^{3+}/Mn^{2+}} \), \( \mathrm{Fe^{3+}/Fe^{2+}} \) and \( \mathrm{Co^{3+}/Co^{2+}} \) that has negative standard electrode potential, is ________ \( \text{B. M.} \). [Nearest integer]
