Laporan III Zulvana

FINAL REPORT

INORGANIC LABWORK

THE STABILITY OF TRANSTITION METAL COMPLEXES TO

CHLORIDE IONS

BY :

Name : Zulvana Anggraeni Harvian

Number of student : 12/327756/PA/14373

Day,Dates : Jumat, 6 Maret 2015

INORGANIC CHEMISTRY LABORATORY

FACULTY OF MATHEMATICS AND NATURAL SCIENCES

UNIVERSITAS GADJAH MADA

YOGYAKARTA

2015

RATIFICATION PAGE

LABWORK REPORT

THE STABILITY OF TRANSITION METAL COMPLEXES TO

CHLORIDE ION

Has been prepared and compiled by

Zulvana A. Harvian

12/327756/PA/14373

Has been collected and checked by Assistant

on March 17th

2015

Assistant Practicant

Benny Wahyudianto Zuvaana A. Harvian

THE STABILITY OF TRANSITION METAL COMPLEXES TO

CHLORIDE ION

ZULVANA ANGGRAENI HARVIAN

12/327756/PA/14373

ABSTRACT

The aims of the experiments is To learn the effect of chloride ion

concentration in the forming of chlor complex from iron metal ion and nickel in

ion exchange resin.

In the laboratory, the Anion Exchange Resin had already set up by the

assistant. So firstly prepared the HCL in some different concentration and

prepared the mixing solution of Fe3+

,Co2+,

Ni2+

. Let the solution just one space up

to the border. HCL added again three times and put the eluate in different test

tubes labeled based on th concentration.

For checking the Fe3+

ion used KCNS the result would be dark red. For

checking the Co2+

ion used NH4CNS 10% in acetone and the result would be blue.

For checking the Ni2+

ion it needed to change the solution was being in basic

condition first by the addition of Ammonia and identified by the lakmus paper

then added the reagent of dimethyl gliocyn.

From the qualitative test was obtained that the Fe2+, Co2+, and Ni2+ metal

was eluted from resins by the HCl in concentration of 1 M. The metal that eluted

from the resins has unstable structure then it can not attached to the resins.

Keyword : anion exchange resin, Chloride ion, complex compound

THE STABILITY OF TRANSTITION METAL COMPLEXES TO

CHLORIDE IONS

I.) THE AIMS OF EXPERIMENTAL SESSION

To learn the effect of chloride ion concentration in the forming of chlor

complex from iron metal ion and nickel in ion exchange resin

II.) THEORITICAL BACKGROUND

Crystal Field Theory

The crystal field theory, in spite of age and relative simplicity, is a

powerful tool to elucidate many spectroscopic, magnetic, and

thermodynamic properties of transition-metal complexes and solid-

state compounds. It finds application in the field of inorganic and

materials chemistry, catalysis, metallorganic, and bioinorganic

chemistry and a vast literature is available on the topic. (Morpurgo,

2007)

Notwithstanding the problem of spinorbit coupling, the crystal

field theory is based on two main approximations, namely the

weak-field and the strong-field approximations, depending on the

relative weight of interelectronic repulsion and crystal field as

energy contributions. Symmetry and spin multiplicity of the

spectroscopic terms of a given transition-metal complex are

independent of the field strength and depend only (i) on the dn

electron configuration of the transition metal involved and (ii) on

the geometrical properties (point group) of the complex itself. The

relative energy of the terms depends, instead, on the field strength

(Morpurgo, 2007)

In Crystal Field Theory, it is assumed that the ions are simple

point charges (a simplification). When applied to alkali metal ions

containing a symmetric sphere of charge, calculations of bond

energies are generally quite successful. The approach taken uses

classical potential energy equations that take into account the

attractive and repulsive interactions between charged particles (that

is, Coulomb's Law interactions). (Lancashire R. , 2000)

with

E the bond energy between the charges and

q1 and q2 are the charges of the interacting ions and

r is the distance separating them.

For example, consider a molecule with octahedral geometry.

Ligands approach the metal ion along the x, y, and z axes.

Therefore, the electrons in the dz2 and dx2y2 orbitals (which lie

along these axes) experience greater repulsion. It requires more

energy to have an electron in these orbitals than it would to put an

electron in one of the other orbitals. This causes a splitting in the

energy levels of the d-orbitals. This is known as crystal field

splitting. For octahedral complexes, crystal field splitting is

denoted by o (or oct). The energies of

the dz2 and dx2y2 orbitals increase due to greater interactions

with the ligands. The dxy, dxz, and dyz orbitals decrease with

respect to this normal energy level and become more stable.

(Lancashire R. , 2000)

A

c

o

n

s

e

q

u

e

nce of

Figure 1. To understand the splitting of d orbitals in a tetrahedral

crystal field, imagine four ligands lying at alternating corners of a

cube to form a tetrahedral geometry, as shown in the figure below.

The dx2

-y2 and dz

2 orbitals on the metal ion at the center of the cube

lie between the ligands, and the dxy, dxz, and dyz orbitals point

toward the ligands. As a result, the splitting observed in a

tetrahedral crystal field is the opposite of the splitting in an

octahedral complex.

Crystal Field Theory is that the distribution of electrons in the d

orbitals may lead to net stabilization (decrease in energy) of some

complexes depending on the specific ligand field geometry and

metal d-electron configurations. It is a simple matter to calculate

this stabilization since all that is needed is the electron

configuration and knowledge of the splitting patterns. The Crystal

Field Stabilization Energy is defined as the energy of the electron

configuration in the ligand field minus the energy of the electronic

configuration in the isotropic field. (Lancashire, 1998)

CFSE=E=E ligand fieldE isotropic field

The CSFE will depend on multiple factors including:

Geometry (which changes the d-orbital splitting patterns)

Number of d-electrons

Spin Pairing Energy

Ligand character (via Spectrochemical Series)

Anion Exchange Resin

Ion exchange resins are polymers that are capable of

exchanging particular ions within the polymer with ions in a

solution that is passed through them. This ability is also seen in

various natural systems such as soils and living cells. The synthetic

resins are used primarily for purifying water, but also for various

other applications including separating out some elements. Ion

exchange materials are insoluble substances containing loosely

held ions which are able to be exchanged with other ions in

solutions which come in contact with them. These exchanges take

place without any physical alteration to the ion exchange material.

Ion exchangers are insoluble acids or bases which have salts which

are also insoluble, and this enables them to exchange either

positively charged ions (cation exchangers) or negatively charged

ones (anion exchangers). (Alchim, 2003)

F

i

gure 2 : Cation Exchange Resin Schematic Showing Negatively

Charged Matrix and Exchangeable Positive Ions

Physical Properties of Resins Conventional ion exchange

resins consists of a cross-linked polymer matrix with a relatively

uniform distribution of ion-active sites throughout the structure. A

cation exchange resin with a negatively charged matrix and

exchangeable positive ions (cations) is shown in Figure 2. Ion

exchange materials are sold as spheres or sometimes granules with

a specific size and uniformity to meet the needs of a particular

application. The majority are prepared in spherical (bead) form,

either as conventional resin with a polydispersed particle size

distribution from about 0.3 mm to 1.2 mm (50-16 mesh) or as

uniform particle sized (UPS) resin with all beads in a narrow

particle size range. In the waterswollen state, ion exchange resins

typically show a specific gravity of 1.1-1.5. The bulk density as

installed in a column includes a normal 35-40 percent voids

volume for a spherical product. Bulk densities in the range of 560-

960 g/l (35-60 lb/ft3) are typical for wet resinous products.

Chemical Properties of Resins Capacity. Ion exchange

capacity may be expressed in a number of ways. Total capacity,

i.e., the total number of sites available for exchange, is normally

determined after converting the resin by chemical regeneration

techniques to a given ionic form. The ion is then chemically

removed from a measured quantity of the resin and quantitatively

determined in solution by conventional analytical methods. Total

capacity is expressed on a dry weight, wet weight or wet volume

The water uptake of a resin and therefore its wet weight and wet

volume capacities are dependent an the nature of the polymer

backbone as well as an the environment in which the sample is

placed. (R.M Wheaton, L.J Lelvere, 2000)

Strong Base Anion-Exchange Resins. The amine resins

that had been developed with compounds such as m-

phenylenediamine were capable of anion exchange only if the

amine was protonated; that limited their use to acidic solutions.

The presence of covalently bound quaternary ammonium sites on

the polymer allowed anion exchange from neutral and alkaline

solutions since the positive charge on the nitrogen did not depend

upon protonation. These resins were referred to as strong base

resins in order to distinguish them from the weak base resins that

had tertiary amine sites in alkaline solutions. Amberlite IRA-400

was the strong base resin produced by the Rohm & Haas Co.11

The affinity for a series of anions with this resin was determined to

be: citrate > sulfate > oxalate > iodide > nitrate > chromate >

bromide > thiocyanate > chloride > formate > hydroxyl > fluoride

> acetate. Dowex 1 and Dowex 2 were the quaternary amine resins

produced by the Dow Chemical Co. and reported to remove

carbonic acid, silicic acid, amino acids, H2S, and phenol from

aqueous solutions.12 Dowex 2 was applied in a plant that

processed 2,500,000 gallons of water per day and it reduced the

silica level to

III.) EXPERIMENTAL DESIGN

i.) Tools and Material

In tools, it needed one set of anion exchange resin as the main

equipment, some of beaker glasses for putting the solution, then it

needed twetleve test tubes for testing the identification of metal

ions, for measure the solution it also needed volumetric glass and

one piece of glass.

For the materials, it used HCL in some different concentration of

9 M, 5 M, 2 M, and 1 M.Then the Fe3+

solution, Co2+

solution,

Ni2+

solution for the testing materials, then KCNS solution,

NH4CNS 10% in acetone, ammonia solution for making the

solution became base and dimethyl gliocyn,

ii.) Procedures

In the laboratory, the Anion Exchange Resin had already set up by

the assistant. So firstly prepared the HCL for 50 mL in some

different concentration started from 1 M,5 M and 9 M and

prepared the 2 mL of mixing solution of Fe3+

,Co2+,

Ni2+

. In the

resin already put by 2 M of HCL so poured the 9 M of HCL until

1 space of the border resins material. Then added 2 mL of the

mixing solution. Let the solution just one space up to the border.

HCL 9 M added again but in 5 mL in three times and put the

eluate in different test tubes labeled by 5-1,5-2,5-3.With the same

treatment, it done by 5 M and M of HCL in 5 mL but did in four

time.After all of it, Check the metal ion but dropped the solution

in every test tube with the some solution addition on the piece of

glass.

For checking the Fe3+

ion used KCNS 0.1 M and the result would

be dark red. For checking the Co2+

ion used NH4CNS 10% in

acetone and the result would be blue. For checking the Ni2+

ion it

needed to change the solution was being in basic condition first by

the addition of Ammonia 15 M and identified by the lakmus paper

then added the reagent of dimethyl gliocyn.

IV.) RESULT AND DISCUSSION

i.) Table of Result

Concentration /

Metal Ions

Fe3+

Co2+

Ni2+

9 M (1) No color No color +1


9 M (3) No color +1 +1





1 M (1) +1 +2 No color

1 M (2) +2 +3 No color

1 M (3) +3 +3 +2

1 M (4) +4 Red +3 +4

Table 1 : Table of Result

ii.) Discussions

Ion exchange materials are insoluble substances

containing loosely held ions which are able to be exchanged

with other ions in solutions which come in contact with them.

These exchanges take place without any physical alteration to

the ion exchange material. Ion exchangers are insoluble acids

or bases which have salts which are also insoluble, and this

enables them to exchange either positively charged ions (cation

exchangers) or negatively charged ones (anion exchangers).

The affinity of sulphonic acid resins for cations varies with the

ionic size and charge of the cation. Generally the affinity is

greatest for large ions with high valency.

Suppose a resin has greater affinity for ion B than for ion

A. If the resin contains ion A and ion B is dissolved in the water

passing through it, then the following exchange takes place, the

reaction proceeding

to the right (R represents

the resin):

When the resin exchange capacity nears exhaustion, it will

mostly be in the BR form. A mass action relationship applies

where the bracketed entities represent concentrations:

[ ][ ]

[ ][ ]

Q is the equilibrium quotient, and is a constant specific for

the pair of ions and type of resin. This expression indicates that if a

concentrated solution containing ion A is now passed through the

exhausted bed, the resin will regenerate into the AR form ready for

re-use, whilst ion B will be eluted into the water. All large scale

applications for ion exchange resins involved such exhaustion and

regeneration cycles.

. Ion-exchange resins were modified in order to expand

their applicability by binding a metal ion onto a resin through ion

exchange and then reducing it to the zerovalent metal.

The complex is less stable will be eluted (detached) at high

HCl concentration 9 M, if the concentration of chloride ions then

lowered for example to 5 M, the complex chloride ion equilibrates

with aqua complex (ligand water molecules) that are not strongly

bound by the resin and can be separated out of the column. While

the metal ions that form the most stable complexes will not elute

until the chloride ion concentration reached 1 M.

For the explanation based on the reaction above :

1. HCl Concentration at 9 M

a. Fe Metal Ion

[Fe(H2O)6]3+

+ 6 Cl- [FeCl6]

3-

b. Ni Metal Ion

[Ni(H2O)6]2+

+ 6 Cl- [NiCl6]

4- + 6

H2O

c. Co Metal Ion

[Co(H2O)6]2+

+ 6 Cl- [CoCl6]

4- + 6 H2O


a. Fe Metal Ion

[FeCl4]- + 6 H2O [Fe(H2O)6]

3+ + 4 Cl

-

b. Ni Metal Ion

[NiCl4]- + 6 H2O [Ni(H2O)6]

2+ + 4 Cl

-

c. Co Metal Ion

[CoCl4]- + 6 H2O [Co(H2O)6]

2+ + 4 Cl

-


They reached equilibrium because the amount of ligands H2O

and Cl are the same, so that the metal ions formed chlor

complex and aqua complex.

The LFSE of the complexes below are resulted as [FeCl6]3-

complex is 0 and the PEB = 0, for complex [CoCl6]4-

LFSE = -1,2

and PEB = 2. And for complex [NiCl6]2-

LFSE = -0,8 and PEB = 3.

Those are for the concentration of 9 M but for 5 M and 1 M resuted

LFSE value for [Fe(H2O)6]3+

complex is -2,0 and PEB = 2, for

[C(H2O)6]2+

complex LFSE = -1,8 and PEB = 3, and for

[Ni(H2O)6]2+

complex LFSE = -1,2 and PEB = 3. Based on

experimental data proved that Ni is the less stable and the order

obtained is Fe3+

> Co2+

> Ni2+

Based on experimental data the metal ion mostly detected

at the concentration of 1 M because at that concentration happened

equilibrium between Chlor ligand and aqua ligands. So that the

metal detected easily and removed easily from the resin. It has the

same as the related theory.

V.) CONCLUSIONS

The aims of the experiments is To learn the effect of chloride ion

concentration in the forming of chlor complex from iron metal ion and

nickel in ion exchange resin so that based on experimental data and

from the tes obtained that the Fe2+, Co2+, and Ni2+ metal was eluted

from resins by the HCl in concentration of 1 M. The metal that eluted

from the resins has unstable structure then it can not attached to the

resins.

VI.) REFERENCES

Alchim, D. (2003). Ion Exchange Resin. Article of Drew New Zealand.

Alexandratos, S. D. (2009). Ion-Exchange Resins: A Retrospective from

Industrial and Engineering Chemistry Research. Ind.Eng.Chem.Res, 4.

Lancashire, P. R. (1998, December). Crystal Field Stabilization Energy. Retrieved

March Sunday 8th, 2015, from ChemWiki:

http://chemwiki.ucdavis.edu/Inorganic_Chemistry/Crystal_Field_Theory/I

ntroduction_to_Crystal_Field_Theory/Crystal_Field_Stabilization_Energy

Lancashire, R. (2000, - -). Crystal Field Theory. Retrieved March Sunday 8th,

2015, from CHEMWIKI:

http://chemwiki.ucdavis.edu/Inorganic_Chemistry/Crystal_Field_Theory/

Crystal_Field_Theory

Morpurgo, S. (2007). Group Theory and Crystal Field Theory. Journal of

Chemical Education.

R.M Wheaton, L.J Lelvere. (2000). Ion Exchange Resin. Amsterdam: Dow Liquid

Seperation Office.

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