Periodic Table of elements – divided into s, p, d, f blocks

p block • p orbital partially fill

d block • d orbital partially filled • transition element

f block • f orbital partially fill

s block • s orbital partially fill

Periodic Table – s, p d, f block element s block elements • s orbitals partially fill

p block elements • p orbital partially fill

d block elements • d orbitals partially fill • transition elements

1 H 1s1

2 He 1s2

11 Na [Ne] 3s1

12 Mg [Ne] 3s2

5 B [He] 2s2 2p1

6 C [He] 2s2 2p2

7 N [He] 2s2 2p3

8 O [He] 2s2 2p4

9 F [He] 2s2 2p5

10 Ne [He] 2s2 2p6

13 Al [Ne] 3s2 3p1

14 Si [Ne] 3s2 3p2

15 P [Ne] 3s2 3p3

16 S [Ne] 3s2 3p4

17 CI [Ne] 3s2 3p5

18 Ar [Ne] 3s2 3p6

19 K [Ar] 4s1

20 Ca [Ar] 4s2

21 Sc [Ar] 4s2 3d1

22 Ti [Ar] 4s2 3d2

23 V [Ar] 4s2 3d3

24 Cr [Ar] 4s1 3d5

25 Mn [Ar] 4s2 3d5

26 Fe [Ar] 4s2 3d6

27 Co [Ar] 4s2 3d7

28 Ni [Ar] 4s2 3d8

29 Cu [Ar] 4s1 3d10

30 Zn [Ar] 4s2 3d10

n = 2 period 2

3 Li [He] 2s1

4 Be [He] 2s2

Click here video s,p,d,f blocks, Click here video on s,p,d,f notation Click here electron structure

Video on electron configuration

f block elements • f orbitals partially fill

3d

Nuclear charge increase IE increase slowly

3d elec added to 3d sub level

3d elec – shield the outer 4s elec from nuclear charge

Ionization Energy – Transition metal Why IE increases slowly across ? IE Transition metal

Sc Ti V Cr Mn Fe Co

Period 4

Ni Cu

Shielding nuclear charge by 3d electron

+21 +22 +23 +24 +25 +26 +27 +28 +29

4s

Sc Ti V Cr Mn Fe Co Ni Cu Zn

+21 +22 +23 +24 +25 +26 +27 +28 +29 +30

Nuclear pull

Shielding by 3d electron Shielding by 3d electron

↓ Balance increase in nuclear charge

↓ Small increase in IE

↓ Easier to lose outer electron

↓ Variable oxidation state

Transition Metal (d block )

Across period

Cr - 4s13d5 • half filled more stable

Cu - 4s13d10 • fully filled more stable

Ca 4s2

K 4s1

Transition metal have partially fill 3d orbital • 3d and 4s electron can be lost easily • electron fill from 4s first then 3d • electron lost from 4s first then 3d • 3d and 4s energy level close together (similar in energy)

Filling electron- 4s level lower, fill first Losing electron- 4s higher, lose first

3d

4s

d block element with half/partially fill d orbital / sublevel in one or more of its oxidation states

Partially fill d orbital

Lose electron

↓

Formation ions

Sc3+

4s03d0 Zn 2+

4s03d10

Zn → Zn2+ 4s23d10 4s0 3d10

fully fill d orbital

Sc → Sc 3+ 4s23d1 4s0 3d0

empty d orbital

Transition Metal (d block )

NOT Transition element.

NOT Transition element.

О

О

Transition Metal

Physical properties Chemical properties

Element properties Atomic properties

• High electrical/thermal conductivity • High melting point • Malleable • Ductile • Ferromagnetic

• Ionization energy • Atomic size • Electronegativity

Transition Metal ( d block)

Gp 1 Gp 17

Sc

Ionization energy ↓

IE increase ↑ slowly ↓

Shielding of nuclear charge by 3d elec

↓ Electrostatic force

attraction ↓

Atomic size ↓

Decrease ↓ slowly ↓

Shielding of outer electron from

nuclear charge by 3d elec

Electronegativity ↓

EN increase ↑ slowly

Physical Properties

Zn

EN increase ↑

Atomic size decrease ↓

IE increase ↑

• Formation of complex ion • Formation coloured complexes

• Variable oxidation states • Catalytic activity

Formation complex ion Formation coloured complexes

Catalytic activity Variable Oxidation states

molecule adsorp on

surface catalyst

V Cr Mn Fe Co Ni

+2 +2 +2 +2 +2 +2

+3 +3 +3 +3 +3 +3

+4 +4 +4 +4 +4 +4

+5 +5 +5 +5 +5

+6 +6 +6

+7

Transition Metal – Variable Oxidation States

+3 +3 +3 +3 +3 +3

+2 +2 +2 +2 +2

+4 +4 +5

+2

+6 +6 +7

+2

+3

+4

+5

+6

+7

ScCI3 TiCI3 VCI3 CrCI3

MnCI3

FeCI3

CrCI2

MnCI2

FeCI2 CoCI2 NiCI2 CuCI2 ZnCI2

TiCI4

MnCI4 V2O5

Cr2O72-

+2

(VO2)2+

(MnO4)2-

(MnO4)-

oxides oxyanion

chlorides

+2 oxidation state more common +3 oxidation state more common

+3

CoCI3

Oxidation state Mn highest +7 Highest oxidation state exist ↓ Element bond to oxygen (oxide/oxyanion)

Oxidation state +2 common (Co → Zn) ↓ Harder to lose electron ↓ Nuclear charge (NC ↑) from Co - Zn

Oxidation state +3 common (Sc → Fe) ↓ Easier to lose electron ↓ Nuclear charge (NC ↓) from Sc - Fe

Transition metal – variable oxidation state ↓ 4s and 3d orbital close in energy ↓ Easy to lose electron from 4s and 3d level

Ionic bond – more common for lower oxi states TiCI2 – Ionic bond Covalent bond – more common for higher oxi states TiCI4 – Covalent bond

Highest oxidation states – bind to oxygen

Transition Metal

Formation coloured complexes Variable Oxidation states

Sc Ti V Cr Mn Fe Co Ni Cu Zn

+1

+2 +2 +2 +2 +2 +2 +2 +2 +2 +2

+3 +3 +3 +3 +3 +3 +3 +3

+4 +4 +4 +4 +4 +4 +4

+5 +5 +5 +5 +5

+6 +6 +6

+7

+3- most common

oxi state

+ 2- most common

oxi state

+ 7- Highest

oxi state

Click here vanadium ion complexes Click here nickel ion complexes

V5+/ VO2+ - yellow

V4+/ VO2+ - blue V3+ - green V2+ - violet

NiCI2 - Yellow NiSO4 - Green Ni(NO3)2

- Violet NiS - Black

Diff oxidation states

Colour formation

Nature of transition metal

Oxidation state

Diff ligands Shape Stereochemistry

Diff ligand Diff metals

MnCI2 - Pink MnSO4 - Red MnO2 - Black MnO4

- - Purple

Cr2O3 - Green CrO4

2- - Yellow

CrO3 - Red

Cr2O72-

- Orange

Shape/ Stereochemistry

Tetrahedral Octahedral

Blue Yellow

Transition Metal ion • High charged density metal ion • Partially fill 3d orbital • Attract to ligand • Form dative/co-ordinate bond (lone pair from ligand)

Ligand • Neutral/anion species that donate lone pair/non bonding electron pair to metal ion • Lewis base, lone pair donor – dative bond with metal ion

Ligand

+2

Formation complex ion

Transition Metal ion

Neutral ligand Anion ligand

H2O

NH3

CO

CI–

CN–

O2-

OH–

SCN–

: CI :

: .

Monodentate Bidentate

Polydentate

C2O42- C2H4(NH2)2

Drawing complex ion • Overall charged on complex ion • Metal ion in center (+ve charged) • Ligand attach • Dative bond from ligand

+3

4 water ligand attach 4 dative bond Coordination number = 4

6 water ligand attach 6 dative bond Coordination number = 6

Transition metal + ligand = Complex Ion

Coordination number

Shape Complex ion (metal + ligand)

Ligand (charged)

Metal ion (Oxidation #)

Overall charge on complex ion

linear [Cu(CI2)]- CI = -1 +1 - 1

[Ag(NH3)2]+ NH3 = 0 +1 + 1

[Ag(CN)2]- CN = -1 +1 - 1

Square planar

[Cu(CI)4]2- CI = -1 +2 - 2

[Cu(NH3)4]2+ NH3 = 0 +2 +2

[Co(CI)4]2- CI = -1 +2 - 2

Tetrahedral [Cu(CI)4]2- CI = -1 +2 - 2

[Zn(NH3)4]2+ NH3 = 0 +2 + 2

[Mn(CI)4]2- CI = -1 +2 - 2

Octahedral [ Cu(H2O)6]2+ H2O = 0 +2 + 2

[Fe(OH)3(H2O)3] OH = -1 H2O = 0

+3 o

[Fe(CN)6]3- CN = -1 +3 - 3

[Cr(NH3)4CI2]+ NH3 = 0 CI = -1

+3 + 1

Types of ligand: • Monodentate – 1 lone pair electron donor – H2O, F-, CI-, NH3, OH-, SCN- CN-

• Bidentate – 2 lone pair electron donor –1,2 diaminoethane H2NCH2CH2NH2, ethanedioate (C2O4)2-

•Polydentate – 6 lone pair electron donor – EDTA4- (ethylenediaminetetraacetic acid)

Complex ion with diff metal ion, ligand, oxidation state and overall charge

Mn+ L: :L

Mn+ :L

:L

L:

L:

Mn+

:L

:L

:L :L

Mn+

:L

:L

:L

:L

:L

:L

Coordination number – number of ligand around central ion

2

4

4

6

Ligand • Neutral/anion species that donate lone pair/non bonding electron pair to metal ion • Lewis base, lone pair donor – dative bond with metal ion

Neutral ligand Anion ligand

H2O

NH3

CO

CI–

CN–

O2-

OH–

SCN–

: CI : : .

Monodentate

Bidentate Polydentate

C2O42- C2H4(NH2)2

Ligand displacement

Co/CN > en > NH3 > SCN- > H2O > C2O42- > OH- > F- > CI- > Br- > I-

Spectrochemical series

Tetraaqua copper(II) ion

H2O displace by CI-

2+

CI- displace by NH3

Tetrachloro copper(II) ion

Stronger ligand displace weaker ligand

Tetraamine copper(II) ion

О

О

Stronger

ligand

Stronger

ligand

Chelating agent EDTA – for removal of Ca2+

• Prevent blood clotting • Detoxify by removing heavy metal poisoning

4s

3d

Magnetic properties of transition metals

Paired electron – spin cancel – NO net magnetic effect

Ti V Cr Mn Fe Co

Diamagnetism ↓

Paired electron ↓

No Net magnetic effect (Repel by magnetic field)

Ni Zn

Spin cancel

Sc

Spinning electron in atom – behave like tiny magnet

Unpaired electron – net spin – Magnetic effect

Spin cancel Net spin

Paramagnetism ↓

Unpaired electron ↓

Net magnetic effect (Attract by magnetic field)

Material

Diamagnetic Paramagnetic Ferromagnetic

• Iron • Cobalt • Nickel

Zn2+ Mn2+

Click here paramagnetism Click here paramagnetism Click here levitation bismuth Click here levitation

4s

3d

Magnetic properties of transition metals

Ti V Cr Mn Fe Co

Diamagnetism ↓

Paired electron ↓

No Net magnetic effect (Repel by magnetic field)

Zn

Spin cancel Net spin

Sc

pyrolytic graphite

Spin cancel Spin cancel

Paramagnetism ↓

Unpaired electron ↓

Net magnetic effect (Attract by magnetic field)

Diamagnetic Paramagnetic

Click here levitation bismuth Click here levitation

Click here paramagnetism measurement

Vs

Bismuth

Click here paramagnetism

Strong diamagnetic materials

Pt/Pd surface

Transition Metal – Catalytic Activity

Catalytic Properties of Transition metal • Variable oxidation state - lose and gain electron easily. • Use 3d and 4s electrons to form weak bond. • Act as Homogeneous or Heterogenous catalyst – lower activation energy • Homogeneous catalyst – catalyst and reactant in same phase/state • Heterogeneous catalyst – catalyst and reactant in diff phase/state • Heterogenous catalyst- Metal surface provide active site (lower Ea ) • Surface catalyst bring molecule together (close contact) -bond breaking/making easier

Transition metal as catalyst with diff oxidation states 2H2O2 + Fe2+ → 2H2O+O2+Fe3+

H2O2+Fe2+→H2O + O2 + Fe3+

Fe3+ + I - → Fe2+ + I2

Fe2+ ↔ Fe3+

Rxn slow if only I- is added H2O2 + I- → I2 + H2O + O2

Rxn speed up if Fe2+/Fe3+ added Fe2+ change to Fe3+ and is change back to Fe2+ again

recycle

molecule adsorp on

surface catalyst

Pt/Pd surface

Bond break

Bond making

3+

CH2 = CH2 + H2 → CH3 - CH3

Nickel catalyst

Without

catalyst, Ea

CH2= CH2 + H2 CH3 - CH3

Surface of catalyst for adsorption

With catalyst, Ea

adsorption H2

adsorption C2H4

bond breaking making

desorption C2H6

Fe2+ catalyst How catalyst work ?

Activation energy

• Haber Process – Production ammonia for fertiliser/ agriculture

3H2 + N2 → 2NH3

Uses of transition metal as catalyst in industrial process

Iron , Fe

Vanadium (V) oxide, V2O5

Nickel, Ni

Manganese (IV) oxide, MnO2

Platinum/Palladium, Pt/Pd Cobalt, Co3+

Iron , Fe2+ ion

Contact Process – Sulphuric acid/batteries 2SO2 + O2 → 2SO3

Hydrogenation Process- Margerine and trans fat

C2H4 + H2 → C2H6

Hydrogen peroxide decomposition – O2 production

2H2O2→ 2H2O + O2

Catalytic converter – Convertion to CO2 and N2

2CO + 2NO → 2CO2 + N2

Biological enzyme Hemoglobin – transport oxygen

Vitamin B12 – RBC production

NH3

Co3+

O2 Fe2+

Why transition metals ion complexes have diff colour?

Transition Metal – Colour Complexes

Colour you see is BLUE – Blue reflected/transmitted to your eyes - Red/orange absorbed (complementary colour)

Colour you see is Yellow – Yellow reflected/transmitted to your eyes - Violet absorbed (complementary colour)

complementary colour

Blue

transmitted

Wave length - absorbed

Wave length - absorbed

Visible

light

Visible

light

Yellow

transmitted

absorbed

Formation coloured complexes Variable Colours

Click here vanadium ion complexes Click here nickel ion complexes

V5+/ VO2+ - yellow

V4+/ VO2+ - blue V3+ - green V2+ - violet

NiCI2 - Yellow NiSO4 - Green Ni(NO3)2

- Violet NiS - Black

Diff oxidation states

Colour formation

Nature of transition metal

Oxidation state

Diff ligands Shape Stereochemistry

Diff ligands Diff metals

MnCI2 - Pink MnSO4 - Red MnO2 - Black MnO4

- - Purple

Cr2O3 - Green CrO4

2- - Yellow

CrO3 - Red

Cr2O72-

- Orange

Shape/ Stereochemistry

Tetrahedral Octahedral

Blue Yellow

Transition Metal – Colour Complexes

Ion Electron configuration

Colour

Sc3+ [Ar] colourless

Ti3+ [Ar]3d1 Violet

V3+ [Ar]3d2 Green

Cr3+ [Ar]3d3 Violet

Mn2+ [Ar]3d5 Pink

Fe2+ [Ar]3d6 Green

Co2+ [Ar]3d7 Pink

Ni2+ [Ar]3d8 Green

Cu2+ [Ar]3d9 Blue

Zn2+ [Ar]3d10 colourless

Ion configuration Colour

Ti3+ [Ar] 3d1 Violet

V3+ [Ar] 3d2 Green

Cr3+ [Ar] 3d3 Violet

Mn2+ [Ar] 3d5 Pink

Fe2+ [Ar] 3d6 Green

Co2+ [Ar] 3d7 Pink

NO ligand • Degenerate • 3d orbital same energy level • five 3d orbital equal in energy

Five 3d orbital (Degenerate – same energy level)

Transition Metal – Colour Complexes

Presence of ligand • 3d orbital split • five 3d orbital unequal in energy

Mn2+ [Ar]3d5

3d yz 3d xy 3d xz 3d Z2 3dx

2 - y2

∆E

lies between axes lies along axes

Mn2+

:L :L :L

Colour- Splitting 3d orbital by ligand

:L :L :L

:L

:L

:L

:L

:L

:L

3d xy 3d xz 3d yz 3dx2 - y

2 3d Z2

No ligand – No repulsion – No splitting 3d orbitals

Mn2+

No ligands approaching

:L

:L

:L

:L

:L

:L

:L

:L :L

:L :L

:L

:L

:L :L

:L :L

:L

:L

:L

:L

:L

:L

:L

Ligands approaching

Ligand approach not directly with 3d electron

Less repulsion bet 3d with ligand

Lower in energy

Ligand approach directly 3d electron

More repulsion bet 3d with ligand

Higher in energy

With ligand

• Splitting of 3d orbital

• 3d orbital unequal energy

Elec/elec repulsion bet

3d e with ligand

Colour- Splitting of 3d orbital of metal ion by ligand

NO ligand • Degenerate • 3d orbital same energy level • five 3d orbital equal in energy

Five 3d orbital (Degenerate – same energy level)

Splitting 3d orbital

Electronic transition possible

Photon light absorb to excite elec

With ligand • Splitting of 3d orbital • 3d orbitals unequal energy

Why Ti 3+ ion solution is violet ?

violet

Transition Metal – Colour Complexes

Presence of ligand • 3d orbital split • five 3d orbital unequal in energy

Ti3+ [Ar] 3d1

3d yz 3d xy 3d xz 3d Z2 3d x

2 - y2

Ti3+ [Ar] 3d1 ∆E

Ion configuration Colour

Sc3+ [Ar] colourless

Ti3+ [Ar] 3d1 Violet

V3+ [Ar] 3d2 Green

Cr3+ [Ar] 3d3 Violet

Mn2+ [Ar] 3d5 Pink

Fe2+ [Ar] 3d6 Green

Co2+ [Ar] 3d7 Pink

Ni2+ [Ar] 3d8 Green

Cu2+ [Ar] 3d9 Blue

Zn2+ [Ar] 3d10 colourless

Green / yellow wavelength

- Abosrb to excite electron

О

Colour- Splitting of 3d orbital of metal ion by ligand

NO ligand • Degenerate • 3d orbital same energy level • five 3d orbital equal in energy

Five 3d orbital (Degenerate – same energy level)

Splitting 3d orbital

Electronic transition possible

Photon light absorb to excite elec

With ligand • Splitting of 3d orbital • 3d orbitals unequal energy

Why Cu3+ ion solution is blue ?

Blue

Transition Metal – Colour Complexes

Presence of ligand • 3d orbital split • five 3d orbital unequal in energy

Cu2+ [Ar] 3d9

3d yz 3d xy 3d xz 3d Z2 3d x

2 - y2

Cu2+ [Ar] 3d9 ∆E

Ion configuration Colour

Sc3+ [Ar] colourless

Ti3+ [Ar] 3d1 Violet

V3+ [Ar] 3d2 Green

Cr3+ [Ar] 3d3 Violet

Mn2+ [Ar] 3d5 Pink

Fe2+ [Ar] 3d6 Green

Co2+ [Ar] 3d7 Pink

Ni2+ [Ar] 3d8 Green

Cu2+ [Ar] 3d9 Blue

Zn2+ [Ar] 3d10 colourless

Red / orange wavelength

- Abosrb to excite electron

О

Cu2+

Colour- Splitting of 3d orbital of metal ion by ligand

NO ligand • Degenerate • 3d orbital same energy level • five 3d orbital equal in energy

Five 3d orbital (Degenerate – same energy level)

Splitting 3d orbital

NO electron

NO absorption light

NO electronic transition possible

With ligand • Splitting of 3d orbital • 3d orbital unequal energy

Why Sc 3+ ion solution is colourless ?

Colourless

Transition Metal – Colour Complexes

Presence of ligand • 3d orbital split • five 3d orbital unequal in energy

Sc3+ [Ar] 3d0

3d yz 3d xy 3d xz 3d Z2 3d x

2 - y2

Sc3+ [Ar] 3d0 ∆E

Ion configuration Colour

Sc3+ [Ar] colourless

Ti3+ [Ar] 3d1 Violet

V3+ [Ar] 3d2 Green

Cr3+ [Ar] 3d3 Violet

Mn2+ [Ar] 3d5 Pink

Fe2+ [Ar] 3d6 Green

Co2+ [Ar] 3d7 Pink

Ni2+ [Ar] 3d8 Green

Cu2+ [Ar] 3d9 Blue

Zn2+ [Ar] 3d10 colourless

All wavelength transmitted

Sc3+

NO absorption

white

Colour- Splitting of 3d orbital of metal ion by ligand

NO ligand • Degenerate • 3d orbital same energy level • five 3d orbital equal in energy

Five 3d orbital (Degenerate – same energy level)

With ligand • Splitting of 3d orbital • 3d orbital unequal energy

Why Zn 3+ ion solution is colourless ?

Colourless

Transition Metal – Colour Complexes

Presence of ligand • 3d orbital split • five 3d orbital unequal in energy

Zn2+ [Ar] 3d10

3d yz 3d xy 3d xz 3d Z2 3d x

2 - y2

Zn2+ [Ar] 3d10 ∆E

Ion configuration Colour

Sc3+ [Ar] colourless

Ti3+ [Ar] 3d1 Violet

V3+ [Ar] 3d2 Green

Cr3+ [Ar] 3d3 Violet

Mn2+ [Ar] 3d5 Pink

Fe2+ [Ar] 3d6 Green

Co2+ [Ar] 3d7 Pink

Ni2+ [Ar] 3d8 Green

Cu2+ [Ar] 3d9 Blue

Zn2+ [Ar] 3d10 colourless

Zn2+

All wavelength transmitted Splitting 3d orbital

FULLY FILLED

NO absorption light

NO electronic transition possible

NO absorption

white

Colour- Splitting of 3d orbital of metal ion by ligand

NO ligand • Degenerate • 3d orbital same energy level • five 3d orbital equal in energy

Five 3d orbital (Degenerate – same energy level)

With ligand • Splitting of 3d orbital • 3d orbital unequal energy

Why Cu3+ ion solution is colourless ?

Colourless

Transition Metal – Colour Complexes

Presence of ligand • 3d orbital split • five 3d orbital unequal in energy

Cu+ [Ar] 3d10

3d yz 3d xy 3d xz 3d Z2 3d x

2 - y2

Cu+ [Ar] 3d10 ∆E

Zn2+

All wavelength transmitted Splitting 3d orbital

FULLY FILLED

NO absorption light

NO electronic transition possible

Ion configuration Colour

Sc3+ [Ar] colourless

Ti3+ [Ar] 3d1 Violet

V3+ [Ar] 3d2 Green

Cr3+ [Ar] 3d3 Violet

Mn2+ [Ar] 3d5 Pink

Cu+ [Ar] 3d10 Colourless

Cu2+ [Ar] 3d9 Blue

white

NO absorption

Colour- Splitting of 3d orbital of metal ion by ligand

NO - Absence of ligand • Degenerate • 3d orbital same energy level • five 3d orbital equal in energy

Five 3d orbital (Degenerate – same energy level)

No ligand/Water • NO Splitting 3d orbital • 3d orbital equal energy

Why Cu3+ ion anhydrous is colourless ?

Transition Metal – Colour Complexes

NO ligand • 3d orbital split • five 3d orbital equal in energy

Cu2+ [Ar] 3d9

3d yz 3d xy 3d xz 3d Z2 3d x

2 - y2

Cu2+ [Ar] 3d9

Ion configuration Colour

Sc3+ [Ar] colourless

Ti3+ [Ar] 3d1 Violet

V3+ [Ar] 3d2 Green

Cr3+ [Ar] 3d3 Violet

Mn2+ [Ar] 3d5 Pink

Fe2+ [Ar] 3d6 Green

Co2+ [Ar] 3d7 Pink

Ni2+ [Ar] 3d8 Green

Cu2+ [Ar] 3d9 Blue

Cu2+

Colourless

NO Splitting 3d orbital

NO absorption light

NO electronic transition possible

All wavelength transmit

white

NO absorption

Formation coloured complexes

V5+/ VO2+ - yellow

V4+/ VO2+ - blue V3+ - green V2+ - violet

NiCI2 - Yellow NiSO4 - Green Ni(NO3)2

- Violet NiS - Black

Diff oxidation states

Colour formation

Nature of transition metal

Diff ligands

Diff metals

MnCI2 - Pink MnSO4 - Red MnO2 - Black MnO4

- - Purple

Cr2O3 - Green CrO4

2- - Yellow

CrO3 - Red

Cr2O72-

- Orange

Shape/ Stereochemistry

Tetrahedral Octahedral

Blue Yellow

Transition Metal – Colour Complexes

Ion configuration Colour

Ti3+ [Ar]3d1 Violet

V3+ [Ar]3d2 Green

Cr3+ [Ar]3d3 Violet

Mn2+ [Ar]3d5 Pink

Fe2+ [Ar]3d6 Green

Co2+ [Ar]3d7 Pink

Ni2+ [Ar]3d8 Green

Cu2+ [Ar]3d9 Blue

Colour- Splitting 3d orbital by ligand

Strong ligand (higher charge density) ↓

Greater splitting ↓

Diff colour

Weak ligand (Low charge density) ↓

Smaller splitting ↓

Diff colour

No ligand ↓

No splitting ↓

No colour

Spectrochemical series – Strong ligand → Weak Ligand

Co/CN > en > NH3 > SCN- > H2O > C2O42- > OH- > F- > CI- > Br- > I-

NO ligand – NO splitting

3d orbital (Same energy level)

WEAK ligand – small splitting

3d orbital (Unequal energy)

∆E ∆E

STRONG ligand – greater splitting

3d orbital (Unequal energy)

I- < Br- < CI- < F- < OH- < C2O42- < H2O < SCN- < NH3 < en < Co/CN

Transition Metal – Colour Complexes Colour- Splitting 3d orbital by ligand

Strong ligand (higher charge density) ↓

Greater splitting - ↑∆E Diff colour

Weak ligand (Low charge density) ↓

Smaller splitting - ↓∆ E Diff colour

No ligand ↓

No splitting No colour

Spectrochemical series – Weak ligand → Strong Ligand

NO ligand – NO splitting

3d orbital (Same energy level) WEAK ligand – small splitting

3d orbital (Unequal energy)

∆E ∆E

STRONG ligand – greater splitting

3d orbital (Unequal energy)

Very Strong ligand ↓

Greater splitting - ↑∆E Diff colour

∆E

Ion ES Colour

Cu(CI4)2- 3d9 Colourless

Cu(CI4)2- 3d9 Green

Cu(H2O)62+ 3d9 Blue

Cu(NH3)42+ 3d9 Violet

Cu2+ [Ar] 3d9

Cu2+

STRONGEST ligand – greatest splitting

О

О

О

Ligand I- Br- CI- F- C2O42- H2O SCN- NH3 en Co/CN-

ʎ (wave

length) longest shortest

∆E Weak field Smallest

Split

Strong field

Highest Split

[Cu(CI)4]2- [Cu(NH3)4]

2+ [Cu(H2O)6]2+

О

О

О

H2O stronger ligand

↓

Greater spitting ∆E

↓

Higher energy wavelength absorbed

CI- weak ligand

↓

Small spitting ∆E

↓

Low energy wavelength absorbed

NH3 strongest ligand

↓

Greatest spitting ∆E

↓

Highest energy wavelength absorbed

- Higher energy absorbed

- Orange wavelength absorb to excite electron

- Highest energy absorbed

- Yellow wavelength absorb to excite electron

Transition Metal – Colour Complexes Colour- Splitting 3d orbital by ligand

Strong ligand (higher charge density) ↓

Greater splitting - ↑∆E - Diff colour

Weak ligand (Low charge density) ↓

Smaller splitting - ↓∆ E - Diff colour

Spectrochemical series – Weak ligand → Strong Ligand

WEAK ligand – small splitting

3d orbital (Unequal energy)

∆E ∆E

STRONG ligand – greater splitting

3d orbital (Unequal energy)

Very Strong ligand ↓

Greater splitting - ↑∆E- Diff colour

∆E

Cu(H2O)62+ 3d9 Blue

STRONGEST ligand – greatest splitting

[Cu(NH3)4]2+ [Cu(H2O)6]

2+

- Lower energy absorbed

- Red wavelength absorb to excite electron

[Cu(CI)4]2-

Cu(CI4)2- 3d9 Green Cu(NH3)42+ 3d9 Violet

Nuclear charge - +5

↓

Strong ESF atrraction bet –ve ligand

↓

Greatest splitting ∆E

↓

Highest energy wavelength absorb

Nuclear charge - +3

↓

Strong ESF atrraction bet –ve ligand

↓

Greater splitting ∆E

↓

Higher energy wavelength absorb

Mn(H2O)62+ +2 PINK

Nuclear charge - +2

↓

Weak ESF atrraction bet –ve ligand

↓

Smaller splitting ∆E

↓

Low energy wavelength absorb

- Higher energy absorbed

- Blue wavelength absorb to excite electron

- Highest energy absorbed

- Violet wavelength absorb to excite electron

Transition Metal – Colour Complexes Colour- Splitting 3d orbital by ligand

High nuclear charge / charge density ↓

Greater splitting - ↑∆E - Diff colour

Low nuclear charge /charge density ↓

Smaller splitting - ↓∆ E - Diff colour

Nuclear charge on metal ion

Low nuclear charge – small splitting

3d orbital (Unequal energy)

∆E ∆E

High nuclear charge – greater splitting

3d orbital (Unequal energy)

Highest nuclear charge/charge density ↓

Greatest splitting - ↑∆E- Diff colour

∆E

Fe(H2O)63+ +3 YELLOW

HIGHEST nuclear charge – greatest splitting

Fe(H2O)63+

- Lower energy absorbed

- Green wavelength absorb to excite electron

V(H2O)65+ +5 YELLOW/GREEN

Mn(H2O)62+ V(H2O)6

5+

Oxidation number - +3

↓

Strong ESF atrraction bet –ve ligand

↓

Greater splitting ∆E

↓

Higher energy wavelength absorb

Oxidation number - +2

↓

Weak ESF atrraction bet –ve ligand

↓

Smaller splitting ∆E

↓

Low energy wavelength absorb

Transition Metal – Colour Complexes Colour- Splitting 3d orbital by ligand

Higher oxidation number/charge density ↓

Greater splitting - ↑∆E - Diff colour

Lower ESF attraction – small splitting

3d orbital (Unequal energy)

∆E ∆E

STRONG ligand – greater splitting

3d orbital (Unequal energy)

∆E

Fe(H2O)63+ +3 Yellow

- Lower energy absorbed

- Red wavelength absorb to excite electron

Fe(H2O)62+ +2 Green

Oxidation number on metal ion

Low oxidation number /charge density ↓

Smaller splitting - ↓∆ E - Diff colour

Fe(H2O)62+

- Higher energy absorbed

- Blue wavelength absorb to excite electron

Fe(H2O)63+

V(H2O)65+ +5 YELLOW/GREEN

Highest oxidation number/charge density ↓

Greatest splitting - ↑∆E- Diff colour

HIGHEST nuclear charge – greatest splitting

- Highest energy absorbed

- Violet wavelength absorbed to excite electron

Nuclear charge - +5

↓

Strongest ESF atrraction bet –ve ligand

↓

Greatest splitting ∆E

↓

Highest energy wavelength absorb

V(H2O)65+

∆E

:L :L

:L

:L :L :L

:L

:L

Cu2+

Ligand tetrahedrally

:L

:L

:L

:L

:L

:L

:L

:L :L

:L :L

:L

:L

:L :L

:L :L

:L

:L

:L

:L

:L

:L

:L

Ligand octahedrally

Ligand approach not directly with 3d elec

Less repulsion bet 3d with ligand

Lower in energy

Ligand approach directly 3d elec

More repulsion bet 3d with ligand

Higher in energy

Greater

Splitting

Elec/elec repulsion bet

3d elec with ligand

Transition Metal – Colour Complexes Colour- Splitting 3d orbital by ligand

Shape of complex ion Complex ion – Octahedral- Cu(H2O)6

2+

Cu(H2O)62+ 3d9 Blue Cu(H2O)4

2+ 3d9 Green

Complex ion – Tetrahedral- Cu(H2O)42+

Cu2+

More ligands – more repulsion ↓

Greater splitting - ↑∆E - Diff colour

Less ligands – less repulsion ↓

Smaller splitting - ↓∆E - Diff colour

:L

:L

:L :L

:L

:L :L

:L

:L

:L :L

:L

:L

:L :L

:L

:L

:L

:L

:L

:L

:L

:L :L

:L :L

:L :L

Elec/elec repulsion bet

3d elec with ligand

Ligand approach directly 3d elec

More repulsion bet 3d with ligand

Higher in energy

∆E

Ligand indirectly with 3d elec

Less repulsion

Lower in energy

Smaller

Splitting

Tetrahedrally Octahedrally