Preparation, Properties and Geometry of Xenon Fluorides
Xenon fluorides are compounds of xenon and fluorine. It can be prepared by heating xenon and fluorine in different ratios at different temperatures and pressures in a nickel vessel. Xenon forms several fluorides such as xenon difluoride (XeF2), xenon tetrafluoride (XeF4), and xenon hexafluoride (XeF6).
Preparation, Properties and Geometry of XeF2
Preparation of XeF2
XeF2 is prepared by heating Xe and F2 in ratio of 2:1 in a Ni-tube at 400°C.
Properties of XeF2
1. XeF2 is a colorless crystalline solid having melting point 127°. It is soluble in liquid HF but solution does not conduct electricity because XeF2 is not ionized.
2. It react quantitatively with hydrogen to form HF.
XeF2 + H2 = 2HF + Xe
3. XeF2 hydrolysed rapidly in alkaline medium but slowly in other medium.
2XeF2 + 2H2O = 2Xe + O2 + 4HF
2XeF2 + 2NaOH = 2Xe + O2 + 4NaF + 2H2O
4. XeF2 forms addition compounds with pentafluorides of P, As, Sb, Nb and Ta.
XeF2 + PF5 = [XeF]+[PF6]−
5. XeF2 is a good oxidizing agent.
XeF2 + 2HCl = 2HF + Xe + Cl2
6. XeF2 is a mild fluorinating agent.
CH2 = CH2 + XeF2 → F – CH2 – CH2 – F + Xe
7. XeF2 reduced to Xe with SO2
XeF2 + 2SO2 = Xe + ½O2 + S2O3F2
8. XeF2 reacts with NO to produce nitrosyl fluoride.
XeF2 + 2NO = 2NOF + Xe
Structure and Shape of XeF2
Hybridization: sp3
Structure: Trigonalbipyramidal
Shape: Linear
Preparation, Properties and Geometry of XeF4
Preparation of XeF4
XeF4 is prepared by heating Xe and F2 in ratio of 1:5 in a Ni-tube at 400°C and high pressure.
Xe + 2F2 → XeF4
Properties of XeF4
1. XeF4 is a colorless crystalline solid having melting point 117°. It readily sublime with white fumes. It is soluble in HF and IF5.
2. XeF4 react with hydrogen to form HF.
XeF4 + 2H2 = Xe + 4HF
3. XeF4 reacts with Xe to form XeF2
XeF4 + Xe = 2XeF2
4. With F2, XeF4 forms XeF6
XeF4 + F2 = XeF6
5. XeF4 oxidizes HCl to Cl2
XeF4 + 4HCl = Xe + 4HF + 2Cl2
6. XeF4 fluorinates ethene.
2CH2 = CH2 + XeF4 → F – CH2 – CH2 – F + CHF2 – CH3 + Xe
7. XeF4 undergoes slow hydrolysis with moisture and forms XeO3 which is highly explosive.
6XeF4 + 12H2 = 4Xe + 2XeO3 + 3O2 + 24HF
But, if the reaction is controlled at – 80°C, it forms xenon oxyfluoride;
XeF4 + 2H2O → XeOF2 + HF
8. XeF4 is a good oxidizing agent.
XeF4 + 2Hg = Xe + 2HgF2
XeF4 + 4KI = 4KF + Xe + 2I2
3XeF4 + 4BCl3 = 3Xe + 4BF3 + 6Cl2
Structure and Shape of XeF4
Hybridization: spd3d2
Structure: Square Pyramidal
Shape: Square Planar
Preparation, Properties and Geometry of XeF6
Preparation of XeF6
XeF6 is prepared by heating Xe and F2 in ratio of 1:20 in a Ni-tube at 973K and under 200 atm. pressure.
Xe + 3F2 → XeF6
Properties of XeF6
1. XeF6 is most volatile in all xenon fluorides. The crystals are white below 42° and becomes light yellow at high temperature. It melts at 46°. XeF6 dissolves in HF but differs from XeF2 and XeF4 by giving a conducting electrolyte.
XeF6 + HF → [XeF5]+ + [XeF2]−
2. XeF6 attacks silica to produce XeOF4
XeF6 + SiO2 = XeOF4 + SF4
3. XeF6 react with hydrogen quantitatively.
XeF6 + 3H2 = 6HF + Xe
4. It react violently with water but slow hydrolysis by atmospheric moisture gives the highly explosive solid XeO3.
XeF6 + 3H2O = XeO3 + 6HF
With small quantity of water, partially hydrolysed to give colorless liquid XeOF4.
XeF6 + H2O = XeOF4 + 2HF
5. XeF6 acts as fluoride acceptors with RbF and CsF
XeF6 + RbF = Rb+[XeF7]−
6. XeF6 forms addition compounds with Sb, As or B fluorides.
XeF6 + SbF5 = [XeF5]+ [SbF6]−
XeF6 + BF3 = [XeF5]+ [BF6]−
7. With silica, XeF6 react to form XeOF4 and XeO3 and so it can not be stored in silica or pyrex glass vessel.
2XeF6 + SiO2 = 2XeOF4 + SiF4
2XeOF4 + SiO2 = 2XeO2F2 + SiF4
2XeO2F2 + SiO4 = 2XeO3 + SiF4
Structure and Shape of XeF6
Hybridization: spd3d3
Structure: Pentagonalbipyramidal
Shape: Distorted Octahedral
