Magnetic properties and spin-only formula
Coordination Compounds · Chemistry
Study notes
A Co²⁺ complex has μ = 4.4 BM. Deduce its spin state and geometry hint. Step 1: Co²⁺ is d⁷. Try n=3: μ = √3(5) = √15 ≈ 3.87 BM. Step 2: Observed 4.4 > 3.87 — orbital contribution inflates it (common for Co²⁺). Step 3: n=3 unpaired → high-spin d⁷ (t₂g⁵e_g²). Step 4: Low-spin d⁷ would give n=1 (1.73 BM) — ruled out. Magnetism reveals electron config!