⚛️ K₃[Fe(CN)₆] — Mössbauer tahlili

Fe³⁺ (LS, d⁵) • δ = −0.12 mm/s • ΔE_Q = 0.38 mm/s • Dublet • Paramagnit

K₃[Fe(CN)₆]

Mössbauer tahlili — to'liq profil

"Qizil qon tuzi" — Fe³⁺ LS klassikasi

K₃[Fe(CN)₆] — Fe³⁺ (LS, t₂g⁵) ning klassik namunasi. Kuchli maydon ligandlari (CN⁻) tufayli quyi spinli (LS) holat. Mössbauer spektri — dublet (δ = −0.12 mm/s, ΔE_Q = 0.38 mm/s). δ past — yuqori oksidlanish va kuchli kovalent bog'. ΔE_Q kichik — deyarli sferik simmetriya.

Fe³⁺ (LS)

d⁵, t₂g⁵

S = 1/2

δ = −0.12

mm/s

izomer siljish

ΔE_Q = 0.38

mm/s

kvadrupol

Dublet

2 cho'qqi

spektr turi

📊 Mössbauer spektr simulyatori — K₃[Fe(CN)₆]

💎 K₃[Fe(CN)₆] ning o'ziga xosligi:

Fe³⁺ (LS, t₂g⁵) — kichik kvadrupol bo'linishi (ΔE_Q = 0.38 mm/s). Sababi: t₂g⁵ konfiguratsiya deyarli sferik simmetrik (bitta toq elektron t₂g da). Izomer siljish δ = −0.12 mm/s — Fe³⁺ LS uchun xarakterli.

δ (izomer siljish):-0.12 mm/s

ΔE_Q (kvadrupol):0.38 mm/s

Γ (chiziq kengligi):0.25 mm/s

Harorat (T):298 K

Mössbauer spektri (⁵⁷Fe, 14.4 keV):

-0.12 mm/s

ΔE_Q

0.38 mm/s

Spektr

Dublet

💡 Kuzatishlar:

Harorat pastlashi → intensivlik oshadi (Lamb-Mössbauer faktor)
ΔE_Q oshsa → ikki cho'qqi orasi kengayadi
δ siljishi → ikkala cho'qqi birga siljiydi
Γ kichik → yuqori rezolyutsiya, aniq cho'qqilar

📐 δ va ΔE_Q tahlili — nima uchun bunday?

δ = −0.12 mm/s — nima anglatadi?

✓ Fe³⁺ — yuqori oksidlanish darajasi
✓ LS holat — t₂g⁵, s-elektron zichligi yuqori
✓ Kuchli π-akseptor (CN⁻) — s-elektronlar metalldan tortiladi
✓ Kovalent bog' — Fe−C kuchli kovalent

Taqqoslash:

Fe³⁺ HS: δ ≈ 0.4 mm/s

Fe³⁺ LS: δ ≈ 0.0 mm/s ← K₃[Fe(CN)₆]

ΔE_Q = 0.38 mm/s — nima anglatadi?

✓ Kichik ΔE_Q — deyarli sferik simmetriya
✓ t₂g⁵ konfiguratsiya — bitta toq elektron
✓ Valentlik hissasi kichik — asimmetriya kam
✓ Oktaedrik simmetriya — EFG kichik

Taqqoslash:

Fe²⁺ HS: ΔE_Q ≈ 3.0 mm/s

Fe³⁺ LS: ΔE_Q ≈ 0.4 mm/s ← K₃[Fe(CN)₆]

Elektron konfiguratsiya va EFG:

t₂g orbitallar:

↑↓↑↓↑

5 e⁻

e_g orbitallar:

____

0 e⁻

t₂g⁵ → bitta toq elektron → kichik EFG → kichik ΔE_Q

💡 Nima uchun ΔE_Q kichik?

t₂g⁵ konfiguratsiyada bitta toq elektron bor, lekin u t₂g orbitallarida joylashgan. t₂g orbitallari ligandlar orasida joylashgan → elektron zichligi deyarli sferik. Shuning uchun elektr maydon gradienti (EFG) kichik → ΔE_Q kichik.
Fe²⁺ HS (t₂g⁴ e_g²) da esa e_g da elektron bor → katta asimmetriya → katta ΔE_Q.

🔄 K₃[Fe(CN)₆] vs K₄[Fe(CN)₆] — Mössbauer solishtirish

Xususiyat	K₃[Fe(CN)₆]	K₄[Fe(CN)₆]
Fe oksidlanish	+3	+2
Elektron konfiguratsiya	d⁵ (t₂g⁵)	d⁶ (t₂g⁶)
Spin holati	LS (S=1/2)	LS (S=0)
Toq elektronlar	1	0
Magnit holat	Paramagnit	Diamagnit
δ (mm/s)	−0.12	−0.06
ΔE_Q (mm/s)	0.38	0.00
H (Tesla)	0	0
Spektr turi	Dublet	Singlet
Rang	To'q qizil	Sariq

💡 Farq nima uchun?

K₃[Fe(CN)₆] — Fe³⁺ (t₂g⁵) → bitta toq elektron → kichik EFG → dublet.
K₄[Fe(CN)₆] — Fe²⁺ (t₂g⁶) → barcha elektronlar juft → sferik simmetriya → EFG = 0 → singlet.
δ qiymatlari deyarli bir xil (−0.12 vs −0.06) — ikkalasi ham LS, kuchli kovalent bog'.

🌡️ Haroratga bog'liqlik — Lamb-Mössbauer faktor

Lamb-Mössbauer faktor:

f = exp(−k²⟨x²⟩)

k — gamma-nur to'lqin vektori, ⟨x²⟩ — atom tebranishi

Harorat (T):298 K

80 K (suyuq N₂)298 K (xona)400 K

f (recoil-free)

0.742

Intensivlik

74.2%

💡 Amaliy maslahat:

Past haroratda (80-100 K) Mössbauer spektri sezilarli kuchliroq bo'ladi. Sababi: atom tebranishlari kamayadi → recoil-free fraksiya (f) oshadi → signal kuchli. K₃[Fe(CN)₆] uchun xona haroratida ham signal yetarli (f ≈ 0.7).

🏛️ Tarixiy kontekst — K₃[Fe(CN)₆] va Mössbauer

⚗️

1822 — Leopold Gmelin

K₃[Fe(CN)₆] birinchi marta sintez qilingan. "Qizil qon tuzi" deb nomlangan — hayvon qonidan olingan temir bilan bog'liq.

⚛️

1960-70 — Mössbauer tadqiqotlari

K₃[Fe(CN)₆] va K₄[Fe(CN)₆] — Mössbauer spektroskopiyasining klassik namunalari. Fe³⁺ LS va Fe²⁺ LS ning spektrlari aniq farqlangan.

🔬

1970-80 — Koordinatsion kimyo

K₃[Fe(CN)₆] — koordinatsion kimyoning "ishchi oti". LS Fe³⁺ ning elektron strukturasi, spin-orbital coupling, kovalent bog'lanish o'rganilgan.

💡 K₃[Fe(CN)₆] ning ahamiyati:

Klassik LS Fe³⁺ namunasi — Mössbauer, EPR, UV-Vis
Elektrokimyoviy standart — [Fe(CN)₆]³⁻/⁴⁻ jufti
Kuchli π-akseptor ligand (CN⁻) ta'sirini o'rganish
Kovalent bog'lanish darajasini baholash

✅ Asosiy xulosalar

K₃[Fe(CN)₆] — Fe³⁺ LS (t₂g⁵, S=1/2)
δ = −0.12 mm/s — yuqori oksidlanish, kuchli kovalent bog'
ΔE_Q = 0.38 mm/s — kichik, deyarli sferik simmetriya
Spektr — dublet (2 cho'qqi)
H = 0 — paramagnit, xona haroratida magnit tartib yo'q
K₄[Fe(CN)₆] (Fe²⁺ LS) bilan solishtirganda — δ deyarli bir xil, ΔE_Q farqli
Past haroratda (80 K) signal kuchliroq (Lamb-Mössbauer faktor)
Mössbauer — Fe³⁺ LS ni aniq tasdiqlaydi

← Mössbauer birikmalar K₄[Fe(CN)₆] →