6th Lecture on Elements of groups 16, 17 & 18 Chemistry Part I12th Standard by Rizwana Mohammed

1. The Malegaon High School & Jr. College
Malegaon, (Nashik), 423203
6th Lecture on Elements of
groups 16, 17 & 18
Chemistry Part I, 12th Science
By
Rizwana Mohammad

2. Interhalogen compounds:
Two or more halogen atoms combine to form species which may
be ionic or neutral. The neutral molecules are called Interhalogen
compounds.
e.g. ClF, BrF3 etc.
The compound is formed by combination of atoms of different
halogens.

3. Classification:
Depending on their composition, Interhalogen compounds are
classified into four types
Type Example
XX’ ClF, BrF, BrCl, ICl, IBr
XX’3 ClF3, BrF3, IF3
XX’5 ClF5, BrF5, IF5
XX’7 IF7

4. General characteristics of Interhalogen compounds:
1. The compound is considered as the halide of X.
e.g. ClF
2. Interhalogen compounds have even number of atoms 2, 4, 6, 8.
e.g. ClF3 has 4 atoms.
3. The properties of Interhalogen compounds are generally
intermediate between those of the halogens from which they are
made.
4. The central halogen exhibits different oxidation states in different
Interhalogen compounds.
5. Number of X’ atoms in the compounds is always odd.
6. They are all diamagnetic.

5. States of interhalogen compounds at 25°C:

6. Methods of preparation of interhalogen compounds:

7. Some properties of interhalogen compounds:

8. Uses of interhalogen compound:

9. Structures of some interhalogen compounds:

10. Oxidation states of central halogen atom in interhalogen compounds.

11. Compounds of xenon:
a. Preparation of xenon Fluorides:
i. Xe + F2 XeF2
ii. Xe + F2 XeF4
1 : 5
ii. Xe + 2F2 XeF4
iii. Xe + 3F2 XeF6
b. Important chemical reactions of XeF2:
i. Hydrolysis:
2XeF2 + 2H2O → 4HF + 2Xe + O2
ii. Reaction with PF5:
XeF2 + PF5 → XeF2.PF5
Ni tube 400°C,
5-6 atm
electric discharge
-80°C
electric discharge
low temp.
Sea d Ni tubele
400°C

12. Xenon trioxide: (XeO3):
a. Preparation:
3XeF4 + 6H2O → 2Xe + XeO3 + 12HF + 1 ൗ1
2O2
XeF6 + 3H2O → XeO3 + 6HF
Oxyfluorides of Xenon:
Xenon forms the following Oxyfluorides:
XeOF2, XeO2F2, XeO3F2, XeO2F4
a. Preparation:
i. XeF4 + H2O
80°C
XeOF2 + 4HF
XeF6 + H2O → XeOF4 + 2HF
ii. 2XeOF4 + SiO2 → 2XeO2F2 + SiF4
XeOF4 + H2O → XeO2F2 + 2HF

13. Structure of xenon compounds:

14. Uses of helium, neon, argon: