The molar susceptibility mol of the Prussian-blue CsFe[Cr(CN) 6 ] Curie paramagnet is 0.0163 emu/mol at

The molar susceptibility χ_mol of the Prussian-blue CsFe[Cr(CN)₆] Curie paramagnet is 0.0163 emu/mol at 300 K and 0.0094 emu/mol at 200 K (CGSem). Using the CGSem formula μ_eff = 2.828√C in Bohr magnetons per formula unit, the Curie law C = χ_T, and the spin-only as well as g_e = 2 approximation, determine the spin state of Fe²⁺.