The calculated spin-only magnetic moments of K3[Fe(OH)6]\mathrm{K}_3[\mathrm{Fe}(\mathrm{OH})_6]K3[Fe(OH)6] and K4[Fe(OH)6]\mathrm{K}_4[\mathrm{Fe}(\mathrm{OH})_6]K4[Fe(OH)6] respectively are :
3.87 and 4.90 B.M.
5.92 and 4.90 B.M.
4.90 and 4.90 B.M.
4.90 and 5.92 B.M.