URANIUM(VI) FLUORIDE - (7783-81-5)

Introduction

Name: uranium(VI) fluoride; uranium hexafluoride
* IUPAC
CAS Number: 7783-81-5
Chemical Formula: UF6
Molar Mass: 352.0193292 g
State of Matter: colorless solid
Mass Percent: U 67.618 %; F 32.381 % 

Classification

• inorganic

Uses/Function

• "Fluorine is used in the nuclear industries of many countries to make uranium hexafluoride for enrichment of uranium in the fissile 235U isotope...Repeated diffusion of UF6 (g) through porous plugs (or centrifugation of the vapor) concentrates 235UF6 relative to 238UF6, since the speed of diffusion varies inversely as the square root of the molecular mass. This enrichment is not needed for fueling power reactors with good neutron economy, such as the Canadian CANDU system. Gaseous diffusion plants for UF6 are expensive, not least because UF6 is itself an aggressive fluorinating agent and thus must be contained in special fluorine-resistant materials." 1

Physical Properties



Density (g/cm3):
5.09 at room temperature/pressure 2
* - 1 atm pressure

Solubility

Qualitative:

Bonding

Bonding: ionic
Ionic Character: 69.09 %

Thermochemistry

ΔHf° (s): -505 kcal/mol 3 = -2,112.92 kJ/mol
ΔHf° (s): -525.10 kcal/mol = -2197.0 kJ/mol 4
ΔHf° (g): -513.24 kcal/mol = -2147.4 kJ/mol 4
S° (s): 54.4 cal/(mol•K) 5 = 227.61 J/(mol•K)
S° (s): 54.40 cal/(mol•K) = 227.6 J/(mol•K) 6
S° (g): 90.32 cal/(mol•K) = 377.9 J/(mol•K) 6
ΔGf° (s): -485 kcal/mol 7 = -2,029.24 kJ/mol
ΔGf° (s): -494.38 kcal/mol = -2068.5 kJ/mol 8
ΔGf° (g): -493.24 kcal/mol = -2063.7 kJ/mol 8

Reactions

For More Information

Sources

(1) - Swaddle, T.W. Inorganic Chemistry; Academic Press: San Diego, 1997; pp 230-231.
(2) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4-93.
(3) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(4) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 5-16.
(5) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(6) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 5-16.
(7) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(8) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 5-16.
(9) - Swaddle, T.W. Inorganic Chemistry; Academic Press: San Diego, 1997; p 230.