Introduction

We are from Group 6. Our group consists of 10 members. The list of our group members are stated below.

1. Ahmad Zaki Bin Affendi 20614 WS47
2. Chow Luan Jia 20813 WS47
3. How Kim Loong 21069 WS47
4. Ling Hua Sien 21346 WS47
5. Muhamad Ezral Bin Ghazali* 21594 WS47
6. Norfaiza Binti Miswan 21832 WS50
7. Nurul Faseeha Binti Zulkiffli 22042 WS47
8. Shah Hazizul Bin Johari 22259 WS47
9. Su Sin Ling 22438 WS47
10. Wan Khairunnisa BT Wan Abdul Khod 22605 WS47

* - Group leader

Trigger 3

Problem 1
In experiment 1, two students prepared an ion complex from cobalt(II), ammonia and nitrogen dioxide. Before the experiment the students have made a hypothesis that the coordination compounds will produce the same coloured solid. However, the two students obtained solids which are different in color.

Question 1

Determine the name and geometrical shape of the ion complex formed in experiment 1. Calculate the ion charge. Explain the rules and steps in naming coordination compounds.

Answer: According to the research we have done, there are two possibilities:
(a) The ion complex formed might be [Co(NH3)3(NO2)3]-
Name: Triamminetrinitrocobalt(II) ion
Geometrical shape: Octahedral
Ion charge: +2+3(-1) = -1
Coordination number: 6
(b) The ion complex formed might be [Co(NH3)5NO2]+
Name: Pentaamminenitrocobalt(II) ion
Geometrical shape: Octahedral
Ion charge: +2+(-1) = +1
Coordination numberL: 6

Rules and steps in naming coordination compounds are:

1. Cation is named before anion.
2. Within complex ion, ligands are named in alphabetical order before the metal ion.
3. Neutral ligands generally have the molecule name, but there are few exception. Anionic ligands drop the -ide and add "o" after the root name.
4. A numerical prefix indicated the number of ligands of a particular type.
5. If complex ion is an anion, we drop the ending of the metal name and add "-ate".

* Remember there is no spaces between the parts of the name.

Question 2

Explain why the difference in color occured in experiment 1. Give other examples that are caused by the same reason in coordination compounds.

Answer: It is depends on the particular elements, oxidation state and the ligand bound to the metal. Besides, it is also because of the linkage isomerism. This arises when a particular ligand is capable of coordinating to a metal in two different ways. Two coordinations:

1. Nitro isomer - coordinate by N atom ( yellow )
2. Nitrito isomer - coordinate by O atom ( red )

Other examples that are caused by the same reason in coordination compounds are:
Ion complex: [Pd(NH3)2(ONO)2]
This complex also has linkage isomerism.
Formulas: [Pd(NH3)2(ONO)2], [Pd(NH3)2(NO2)2]