⚡ d-orbitallarning energiyasi
Degenerat holat • Kristall maydon ajralishi • KMBE • OTM darajasi
📋 Erkin ionda degenerat holat
Erkin metall ionida barcha 5 ta d-orbital bir xil energiyaga ega — degenerat holat. Ligandlar yaqinlashganda degeneratlik buziladi — orbitallar energetik ajraladi. Bu kristall maydon nazariyasining asosidir.
🎯 Maqsad: Kristall maydon ajralishi, KMBE hisobi, Δ₀ ga ta'sir etuvchi omillarni tushunish.
⏱️ Vaqt: ~3.5 soat
📚 Manba: Cotton — Advanced Inorganic Chemistry; Housecroft — Inorganic Chemistry
dxy = dxz = dyz = dz² = dx²−y² (E₀)
Erkin ionda 5 ta d-orbital — degenerat
⚡ Kristall maydonda energetik ajralish — interaktiv
💡
6 ta ligand. t₂g stabillashgan (−0.4Δ₀), e_g destabillashgan (+0.6Δ₀)
⚖️ Baritsentr qoidasi — energiya saqlanishi
Baritsentr qoidasi: Kristall maydonda orbitallar ajralganda, ularning energiya markazlari (baritsentr) o'zgarmaydi.
3·(−0.4Δ₀) + 2·(+0.6Δ₀) = 0
t₂g da 3 ta orbital (−0.4Δ₀) + e_g da 2 ta orbital (+0.6Δ₀) = −1.2 + 1.2 = 0
💡
Baritsentr qoidasi tufayli KMBE = −0.4·n(t₂g) + 0.6·n(e_g) formula bilan hisoblanadi.
🔧 Δ₀ ga ta'sir etuvchi omillar
1. Oksidlanish darajasi
Oksidlanish darajasi oshgan sari Δ₀ ORTADI.
Sababi:
Yuqori zaryadli metall → ligandlarni kuchliroq tortadi → katta ajralish.
| Kompleks | Faktor | Konfig. | Δ₀ |
|---|---|---|---|
| [Co(H₂O)₆]²⁺ | Co²⁺ | d⁷ | 9 300 cm⁻¹ |
| [Co(H₂O)₆]³⁺ | Co³⁺ | d⁶ | 18 200 cm⁻¹ |
| [Fe(H₂O)₆]²⁺ | Fe²⁺ | d⁶ | 10 400 cm⁻¹ |
| [Fe(H₂O)₆]³⁺ | Fe³⁺ | d⁵ | 14 300 cm⁻¹ |
📊 Spektrokimyoviy qator — Δ₀ va ligand turlari
Spektrokimyoviy qator: I⁻ < Br⁻ < Cl⁻ < F⁻ < OH⁻ < H₂O < NH₃ < en < CN⁻ < CO
π-donor: elektron beradi → t₂g ni destabilizatsiya → kichik Δ₀ (kuchsiz maydon, HS)
π-akseptor: elektron oladi → t₂g ni stabilizatsiya → katta Δ₀ (kuchli maydon, LS)
σ-donor: faqat σ bog' → o'rtacha Δ₀
🧮 KMBE (CFSE) — real vaqtli kalkulyator
Geometriya:
d-elektronlar (dⁿ): 6
Δₒ 25,000 cm⁻¹
📊 KMBE natijalari
KMBE (Δ birligida)
-2.40 Δ
-720.0 kJ/mol
HS
-0.40Δ
-120.0 kJ/mol
Spin: 2
LS
-2.40Δ
-720.0 kJ/mol
Spin: 0
📊 Uchala maydonni taqqoslash
| Xususiyat | Oktaedrik (Oh) | Tetraedrik (Td) | Kvadrat (D4h) |
|---|---|---|---|
| Ajralish | Δ₀ = 10 Dq | Δ_t ≈ 4/9·Δ₀ | Δ_sq > Δ₀ |
| Stabillashgan | t₂g (3): −0.4Δ₀ | e (2): −0.6Δ_t | dxz, dyz: eng past |
| Destabillashgan | e_g (2): +0.6Δ₀ | t₂ (3): +0.4Δ_t | dx²−y²: eng yuqori |
| Yo'nalish | t₂g↓ e_g↑ | t₂↑ e↓ (teskari!) | 4 xil sath |
| Eng yuqori | dx²−y², dz² | dxy, dxz, dyz | dx²−y² (b₁g) |
| Eng past | dxy, dxz, dyz | dz², dx²−y² | dxz, dyz (e_g) |
| Spin | HS yoki LS | Har doim HS | LS (d⁸ uchun) |
| Misol | [Ti(H₂O)₆]³⁺ | [CoCl₄]²⁻ | [PtCl₄]²⁻ |
📝 Bilim tekshirish — 1/10
Oktaedrik maydonda nechta d-orbital t₂g guruhiga kiradi?
✅ Asosiy xulosalar
- Erkin ionda 5 ta d-orbital degenerat
- Oktaedrik: t₂g↓ (−0.4Δ₀) + e_g↑ (+0.6Δ₀) — eng keng tarqalgan
- Tetraedrik: teskari ajralish, Δ_t ≈ 0.44·Δ₀
- Kvadrat: eng katta ajralish, 4 daraja, d⁸ metallar
- Baritsentr qoidasi: 3·(−0.4) + 2·(+0.6) = 0
- Δ₀ ortadi: yuqori oksidlanish, 3d→4d→5d, kuchli ligandlar
- KMBE = −0.4·n(t₂g) + 0.6·n(e_g)
📚 Manbalar: Cotton & Wilkinson — Advanced Inorganic Chemistry | Housecroft — Inorganic Chemistry | Nasimov, Tashpulatov — Noorganik kimyo
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