d⁴ ion: weak field (high spin) vs strong field (low spin)d⁴ आयन: दुर्बल क्षेत्र (उच्च प्रचक्रण) बनाम प्रबल क्षेत्र (निम्न प्रचक्रण)d⁴ ion: weak field (high spin) vs strong field (low spin)
NCERT §5.5.4 · Class 12 Chemistry · Chapter 5 · interactive diagram
Parts and what they mean
- Weak-field ligand: Δo < P (दुर्बल क्षेत्र लिगन्ड: Δo < P) — Pairing costs more than climbing to eg, so the 4th electron enters eg.
- eg level (weak field) (eg स्तर (दुर्बल क्षेत्र)) — The 4th electron goes up here singly.
- t2g level (weak field) (t2g स्तर (दुर्बल क्षेत्र)) — Three electrons singly (Hund’s rule).
- Small Δo (छोटा Δo) — Weak ligands (I⁻, Br⁻, Cl⁻, F⁻ …) split the d orbitals only a little.
- t2g³eg¹: high spin (t2g³eg¹: उच्च प्रचक्रण) — Four unpaired electrons; matches [MnCl₆]³⁻ (NCERT: four unpaired).
- Strong-field ligand: Δo > P (प्रबल क्षेत्र लिगन्ड: Δo > P) — Pairing in t2g is cheaper than climbing the big gap.
- eg level (strong field) — empty (eg स्तर (प्रबल क्षेत्र) — खाली) — Too high to be worth it.
- t2g level (strong field) (t2g स्तर (प्रबल क्षेत्र)) — The 4th electron pairs here.
- Large Δo (बड़ा Δo) — Strong ligands (NH₃, en, CN⁻, CO) split strongly.
- t2g⁴eg⁰: low spin (t2g⁴eg⁰: निम्न प्रचक्रण) — Two unpaired electrons; matches [Mn(CN)₆]³⁻ (NCERT: two unpaired).
Original diagram drawn by Simple Learning Hub, based on NCERT §5.5.4. Report a mistake