The document discusses the chemistry of noble gases, focusing on xenon. It provides information on: 1) Xenon's electronic configuration which allows it to form stable compounds with highly electronegative elements like fluorine under extreme conditions. 2) The synthesis and properties of xenon fluorides (XeF2, XeF4, XeF6) which are strong oxidizing agents. XeF6 in particular is the strongest known fluorinating agent. 3) Xenon can also form oxides when reacted with oxygen or hydrolyzed. Unstable compounds include xenon tetroxide (XeO4) and xenon trioxide (XeO3).

1. Chemistry of Nobel gases
Course: B.Sc.
Microbiology/Biotechnology/Biochemistry
Sem II
Sub: Inorganic Chemistry
Unit 4.1

2. • That group VIII elements are called the Noble gases.
• The physical and chemical properties of group VIII
elements, the Noble gases.
• That they have similar chemical and physical properties
based on their electronic configuration.
• That because of their full outer shells, the Noble gases do
not form compounds with other metal or non metal
elements.
• Understand that their discovery in the atmosphere was
hampered by their stability.
• Some of the main uses of the Noble gases.

3. Fr Ra Ac Rf Db Sg Bh Hs Mt Ds Rg ? ? ? ? ? ? ?
Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br
Na Mg Al Si P S Cl
Li Be B C N O F
H
Rn
Xe
Kr
Ar
Ne
He
Group 0 – the noble gases
Noble gases are in group 0 of the periodic table, on the right.
Rn
Xe
Kr
Ar
Ne
He
0

4. helium
2
neon
2,8
argon
2,8,8
Electron structure and reactivity
 They do not normally form bonds with other
elements.
All noble gases have full outer electron shells and do not need to gain, lose or share
electrons.
 They are very stable and the most
unreactive (or inert) of all the elements.
 They are monatomic, which means they exist
as individual atoms. Most other gases are
diatomic.
This means that:

5. Chemical properties of Noble gas
• odorless ,
• colorless,
• nonflammable,
monotonic gases : low chemical reactivity.

6. General properties of noble gases
All noble gases are colourless, odourless and unreactive. This makes them difficult to
isolate and identify.
Because noble gases are so unreactive, there are few patterns, or trends, among the
group.

7. • increase in density : increase in atomic mass
• increasing in atomic size : the electron clouds
of these non polar atoms - increasingly
polarized which leads to weak van Der Waals
forces among the atoms.
• formation of liquids and solids is more easily
attainable for these heavier elements because
of their melting and boiling points.

8.  density – A measure of mass in a given volume. Often expressed in g/dm3.
 inert – Describes a substance that is unreactive under normal conditions.
 monoatomic –An element that exists as a single atom.
 noble gas – An element belonging to group 0 of the periodic table.
 trend – A gradual change in a property or characteristic of elements in the same
group of the periodic table.

9. History of Noble Gas Compounds
1962, Bartlett and Lohmann:
• demonstrated the great oxidizing strength of PtF6 in producing
O2
+PtF6
-
• IP(Xe) ≈ IP(O2)
Xe + PtF6 XePtF6 + Xe(PtF6)2
RT
- dependent on reactant ratio
- red-tinged yellow solid
Graham, L.; Graudejus, O.; Jha, N. K.; Bartlett, N. Concerning the nature of XePtF6. Coord. Chem. Rev. 2000, 197, 321-334.

10. Chemistry of Xenon
• symbol : Xe ,
• atomic number : 54.
• colorless, heavy, odorless noble gas ,
• Occurrence :
• earth's atmosphere in trace amounts.
one part in twenty million.
commercially : extraction from the residues of liquefied air.
- naturally found in gases emitted from some mineral
springs.
- Xe-133 and Xe-135 are synthesized : neutron irradiation
within air-cooled nuclear reactors.

11. Xenon Fluorides
• readily preparable from the elements
• thermodynamically stable
XeF2
XeF4
XeF6
• not known: XeF8
Compounds of Xenon

12. XeF2
• first prepared 1962
• colorless as solid, liquid, or gas
• homogeneous reaction
Xe + F2 XeF F
electric discharge, heat,
UV light, sunlight
cat. HF
• thermal heterogeneous reaction using solid NiF2
• production favored with low F pressures and high temp

13. XeF2
•large crystals at RT
• shape : body-centered tetragonal
•strong interactions between XeF2 molecules (high ΔHsub)
•soluble in BrF3, BrF5, IF5; sometimes forms complexes
• soluble in organic solvents such as MeCN
• strong oxidizer .
• stable in aqueous solution
•Mild fluorinating agent for organic compound.
•E.g., C6H5F.

14. XeF4
• first noble gas binary fluoride synthesized
Xe + F2 XeF F
1 : 5 tot pressure 0.6 MPa
673 K
closed nickel can
F
F
• colorless as crystals, liquid, or vapor
• strong oxidative fluorinator : fluorinate aromatic rings in
compounds ( Toluene)

15. Molecular packing, projection down b axis
XeF4
• square planar in gas phase
• nearly square planar as a solid
• strong electrostatic interactions between molecules in solid
Zemva, B. Noble Gases: Inorganic Chemistry. In Encyclopedia of Inorganic Chemistry; King, R. B., Ed.; John Wiley & Sons:
New York, 1994; pp 2660-2680.

16. XeF6
• interaction of XeF4 & F2 at 250° C , Pressure – greater than 50
atm.
•Extermely reactive.
•production favored with high F pressures and low temp
• solid is colorless; liquid and vapor are yellow-green
• more volatile than XeF2 or XeF4
• controversy over crystal structure of solid
Xe + 3F2 → XeF6

17. • more powerful oxidizer and fluorinator than XeF2 or XeF4
• strongest fluorinating agent
• Colorless solid
• Exergonic and stable at normal temperatures
• Sublimates into yellow vapors
• Structure lacks perfect octahedral symmetry

18. • Xenon trioxide (XeO3)
XeO3 prepared by the slow hydrolysis of XeF6
XeF6 + 3H2O ------------> XeO3 + 6HF
- soluble in water,
• Colorless & odorless
• aqueous solution : weakly acidic.
XeO3 + H2O <--------> H+ + HXeO4 – Xenate ion
• pyramidal structrure
• Xe : sp3 hybridisation.

20. • Xenon tetroxide (XeO4)
- treating barium perxenate (Ba2XeO6) with anhydrous
sulphuric acid.
Ba2XeO6 + 2H2SO4 -----------> XeO4 + 2BaSO4 + 2H2O
- highly unstable,
• tetrahedral structure.

21. References
• Advanced Inorganic Chemistry by Volume I, Satyaprakash, G D Tuli,
S. K. Basu, R. D. Madan
• Modern Inorganic Chemistry’ G. F. Liporni, ELBS, 4th edition, Collins
educational, 1983