Coordination complex preparation

1. DOS & R IN ORGANIC CHEMISTRY 1
TUMKUR UNIVERSITY
TUMAKURU
DEPARTMENT OF STUDIES AND
RESEARCH IN ORGANIC CHEMISTRY
INORGANIC CHEMISTRY PRACTICAL MANUAL
Prepared By
Dr. S. Sreenivasa Ph.D., D.Sc.
Associate Professor
Dr. G. Krishnaswamy Ph.D.
Faculty

2. DOS & R IN ORGANIC CHEMISTRY 2
Preparation of Hexaamminecobalt(III)chloride
AIM: To prepare Hexaamminecobalt(III)chloride from ammonium chloride and
Cobaltous chloride hexa hydrate.
CHEMICALS REQUIRED: CoCl2.6H2O, NH4Cl, Liq. NH3, H2O2, Charcoal
PROCEDURE:
➢ Dissolve 2.0 g of CoCl2.6H20 and 1.5g of NH4Cl in 4ml of water in beaker.
Then add 0.25 g of animal charcoal. Cool the reaction mixture in ice-bath.
Add 5ml of Conc.NH3 and maintain the solution at 100
C or lower.
➢ Add slowly in small portions 5ml of H2O2 with stirring .Then gradually rise
the temperature to 50-600
C and maintain this temperature until last traces of
pink color is removed.
➢ Then cool and decant the solution through funnel containing filter paper
keeping crystals in the beaker. Transfer if any crystals on filter paper.
Dissolve it by boiling H2O containing HCl. Except charcoal all crystals will
dissolve in boiling H2O containing HCl.
➢ Filter the filtrate while hot. Cool the filtrate in an ice-bath to get golden
brown crystals.
➢ Dry the crystals by placing them between pieces of filter paper.
➢ Determine the weight. Report the yield and percentage yield.
REACTION:
CoCl2 •6H2O + 5NH3 + NH4Cl ↔ [Co(NH3)6]Cl3 + 6H2O + H+

3. DOS & R IN ORGANIC CHEMISTRY 3
Name: Hexaamminecobalt(III)Chloride
Geometry: octahedral
Hybridization: d2
sp3
Magnetic spin: low spin
Number of unpaired electrons: 0
Magnetic moment =
Magnetic property: Diamagnetic
Color: Golden brown

4. DOS & R IN ORGANIC CHEMISTRY 4
OBSERVATIONS AND CALCULATIONS:
THEORETICAL YIELD:
237.92g of CoCl2 .6H2O gives 268.43g of [Co(NH3)6]Cl3
g of CoCl2. 6H2O gives ‘x’ g of [Co(NH3)6]Cl3
x = x 268.43
237.92
X= g
Practical yield:
Percentage yield = practical yield x 100
Theoretical yield
=
REPORT:
Name and
structure of the
complex
Theoretical yield Practical yield Percentage yield

5. DOS & R IN ORGANIC CHEMISTRY 5
Preparation of Hexaamminenickel(II)chloride
AIM: To synthesize hexamminenickel(II) chloride, using nickel chloride
hexahydrate (NiCl2. 6H2O) and concentrated aqueous ammonia.
MATERIALS REQUIRED: Nickel chloride hexahydrate, concentrated aqueous
ammonia, beakers.
PROCEDURE:
➢ Take 5 ml of a solution of nickel chloride hexahydrate (containing about 6 g
of nickel chloride) in a 100 ml beaker. Stir this solution.
➢ Add 12 ml of concentrated aqueous ammonia, slowly, to a rapidly stirred
solution of nickel chloride.
➢ Make sure that the color of the solution has changed from pale green to
intense violet (if not, add more ammonia).
➢ Allow the solution to stand at room temperature for 5 minutes. Cool in an
ice-bath, without disturbance, for about 15 minutes.
➢ If violet crystals of [Ni(NH3)6]Cl2 have not formed, try initiating the process
of crystallization by gently scratching the sides of the beaker, using a glass
rod.
➢ Filter the solution, and wash the crystals with concentrated aqueous
ammonia solution ( ~ 5 ml).
➢ Dry the crystals by placing them between pieces of filter paper.
➢ Determine the weight. Report the yield and percentage yield.
REACTION:
[Ni(H2O)6]Cl2 (aq) + 6 NH3 (aq) → [Ni(NH3)6]Cl2 (aq) + 6 H2O (l)

6. DOS & R IN ORGANIC CHEMISTRY 6
Name: Hexaamminenickel(II)Chloride
Geometry: octahedral
Hybridization: sp3
d2
Magnetic spin: high spin
Number of unpaired electrons: 2
Magnetic moment =
Magnetic property: Paramagnetic
Color: Violet

7. DOS & R IN ORGANIC CHEMISTRY 7
OBSERVATIONS AND CALCULATIONS:
THEORETICAL YIELD:
237.71 g NiCl2 6H2O gives 231.6 g of [Ni(NH3)6]Cl2
3 g of NiCl2 6H2O gives X g of [Ni(NH3)6]Cl2
X = (3 X 231.6)/231.71 g
X= g
Practical yield:
Percentage yield = practical yield x 100
Theoretical yield
=
REPORT:
Name and
structure of
complex
Theoretical yield Practical yield % yield

8. DOS & R IN ORGANIC CHEMISTRY 8
Preparation of Potassium
Trisoxalatoferrate(III)trihydrate
AIM: To prepare potassium tris(oxalato) iron(III) trihydrate, K3[Fe(C2O4)3] •
3H2O.
MATERIALS REQUIRED: Ferrous ammonium sulphate, oxalate acid dihydrate,
potassium oxalate monohydrate, hydrogen peroxide, beakers.
PROCEDURE:
➢ 5.00 g of ferrous ammonium sulphate was dissolved in 25 ml
distilled water containing 1 ml of diluted sulphuric acid in the beaker.
➢ 2.50g of oxalate acid dihydrate was dissolved in 25 ml of distilled
water in another beaker. Then it was added into the beaker containing
ferrous ammonium sulphate.
➢ The mixture was heated slowly until boiling and then it was
allowed the yellow precipitate to settle. The supernatant was discarded. 15
ml hot water was added into the yellow precipitate. It was stirred and the
supernatant was discarded. 15 ml of hot water was added to precipitate.
➢ 3.5 g of solid potassium oxalate monohydrate. It was heated to
approximately 40o
C. Then immediately 1% ml of H2O2 was added drop
wisely and it was stirred continuously.
➢ It was heated to boiling and the dissolved solution of 2.0 g of
oxalic acid in 30 ml of distilled water was added into the mixture until the
brown precipitate was dissolved.
➢ It was boiled until the solution was clear. The solution was filtered
through Buchner funnel. 30 ml of 95% ethanol was added slowly to the

9. DOS & R IN ORGANIC CHEMISTRY 9
solution. Any crystals were formed was redissolved. Then it was leaved in
not direct light to crystallise for a week.
➢ The crystals were collected by suction filtration process. The
beaker was rinsed with10 ml of 1:1 ethanol-distillation water for two times.
The crystals were washed with cold acetone.
➢ The crystals were placed on the watch glass and it was allowed to
dry on air. The mass of the synthesised crystals and percentage yield were
determined.
REACTION:
FeC2O4 + H2SO4 + (NH4)2SO4 + 6H2O Fe(NH4)2(SO4)2 • 6H2O + H2C2O4
H2O + HO2
(–)
+ 2 Fe(2+)
2 Fe(3+)
+ 3 OH(–)
Fe(3+)
+ 3OH(–)
Fe(OH)3
3K2C2O4 + 2 Fe(OH)3 +3 H2C2O4 2 K3[Fe(C2O4)3] • 3H2O + 3 H2O

10. DOS & R IN ORGANIC CHEMISTRY 10
Name: Potassium tris(oxalato) iron(III) trihydrate
Geometry: octahedral
Hybridization: sp3
d2
Magnetic spin: high spin
Number of unpaired electrons: 2
Magnetic moment =
Magnetic property: Paramagnetic
Color: Green
OBSERVATIONS AND CALCULATIONS:
THEORETICAL YIELD:
392.02 g Fe(NH4)2SO4.6H2O gives 491.21 g of K3[Fe(C2O4)3] • 3H2O.
5 g of Fe(NH4)2SO4.6H2O gives X g of K3[Fe(C2O4)3] • 3H2O.
X = (5 X491.21)/ 392.02 g
X= g
Practical yield:
Percentage yield = practical yield x 100
Theoretical yield
=

11. DOS & R IN ORGANIC CHEMISTRY 11
REPORT:
Name and
structure of
complex
Theoretical yield Practical yield % yield

12. DOS & R IN ORGANIC CHEMISTRY 12
Preparation of Mercurytetrathiocyanatocobaltate (lll)
AIM: To prepare Mercury tetrathiocyanatocobaltate Chloride hexahydrate and
ammonium thiocyanate.
REAGENTS: COCl2.6H2O, HgCl2, NH4SCN, beakers.
PROCEDURE:
➢ Dissolve 2.00 g of Cobaltous Chloride hexahydrate and 2.5 g of ammonium
thiocyanate in 20 ml of boiling water.
➢ This hot solution is then added to clear filtered mercuric Chloride (2.00 g in
10 ml distilled water). Boil the resultant solution for 5- 10 minutes and then
allow it cool to lab temperature.
➢ Decant the supernatant liquid wash the solid with cold water.
➢ Collect the crystals mercurytetrathiocyanocobaltate(II).
➢ Dry the crystals by placing them between pieces of filter paper.
➢ Determine the weight. Report the yield and percentage yield.
REACTION:

13. DOS & R IN ORGANIC CHEMISTRY 13
Name: Mercurytetrathiocyanocobaltate(II)
Geometry: Tetrahedral
Hybridisation: Sp3
Coordination number: 04
Magnitic moment: √n(n+2) = √ 3(3+2) = 3.87
Colour of Complex: Dark blue
Magnitic Property: Paramagnetic
OBSERVATION AND CALCULATION:
THEORITICAL YIELD
237.93 g of CoCl2. 6H2O gives 491.78 g of Hg [Co(SCN )4]
2.00 g of CoCl2. 6H2O gives ‘x’ g of Hg [Co(SCN)4]
X = 491.78 × 2
237.93
X = g
Practical yield:
Percentage yield = practical yield x 100
Theoretical yield
=

14. DOS & R IN ORGANIC CHEMISTRY 14
REPORT:
Name and
structure of
complex
Theoretical yield Practical yield % yield