Spectrochemical series (NCERT order)स्पेक्ट्रमी रासायनिक श्रेणी (NCERT क्रम)Spectrochemical series (NCERT order)

NCERT §5.5.4 · Class 12 Chemistry · Chapter 5 · interactive diagram

Parts and what they mean

• I⁻ — position 1 of 15 (I⁻ — 15 में से स्थान 1) — Weaker field than everything to its right. NCERT notes that anionic ligands sit at the LOW end — something pure CFT cannot explain.
• Br⁻ — position 2 of 15 (Br⁻ — 15 में से स्थान 2) — Weaker field than everything to its right. NCERT notes that anionic ligands sit at the LOW end — something pure CFT cannot explain.
• SCN⁻ — position 3 of 15 (SCN⁻ — 15 में से स्थान 3) — Weaker field than everything to its right.
• Cl⁻ — position 4 of 15 (Cl⁻ — 15 में से स्थान 4) — Weaker field than everything to its right. NCERT notes that anionic ligands sit at the LOW end — something pure CFT cannot explain.
• S²⁻ — position 5 of 15 (S²⁻ — 15 में से स्थान 5) — Weaker field than everything to its right.
• F⁻ — position 6 of 15 (F⁻ — 15 में से स्थान 6) — Weaker field than everything to its right. NCERT notes that anionic ligands sit at the LOW end — something pure CFT cannot explain.
• OH⁻ — position 7 of 15 (OH⁻ — 15 में से स्थान 7) — Weaker field than everything to its right.
• C₂O₄²⁻ — position 8 of 15 (C₂O₄²⁻ — 15 में से स्थान 8) — Middle of the series.
• H₂O — position 9 of 15 (H₂O — 15 में से स्थान 9) — H₂O: weaker than NH₃ — [Fe(H₂O)₆]³⁺ is high spin (5 unpaired), [Fe(CN)₆]³⁻ low spin (1 unpaired).
• NCS⁻ — position 10 of 15 (NCS⁻ — 15 में से स्थान 10) — Stronger field than everything to its left.
• edta⁴⁻ — position 11 of 15 (edta⁴⁻ — 15 में से स्थान 11) — Stronger field than everything to its left.
• NH₃ — position 12 of 15 (NH₃ — 15 में से स्थान 12) — Stronger field than everything to its left.
• en — position 13 of 15 (en — 15 में से स्थान 13) — Stronger field than everything to its left.
• CN⁻ — position 14 of 15 (CN⁻ — 15 में से स्थान 14) — CN⁻: one of the strongest-field ligands — forces pairing: [Fe(CN)₆]³⁻ has only one unpaired electron.
• CO — position 15 of 15 (CO — 15 में से स्थान 15) — CO: the strongest in NCERT’s series (synergic σ + π bonding).
• Weak-field end (दुर्बल क्षेत्र सिरा) — Δo < P → electrons spread out → high spin complexes.
• Strong-field end (प्रबल क्षेत्र सिरा) — Δo > P → electrons pair in t2g → low spin complexes.

Original diagram drawn by Simple Learning Hub, based on NCERT §5.5.4. Report a mistake