92 U Uranium
Appearance: Silvery gray metallic
Mass number: 238
Atomic weight: 238.02891 g/mol
Atomic number (Z): 92
Electrons: 92
Protons: 92
Neutrons: 146
Period: 7
Block: f
Element category: Actinide
Electrons per shell: K2, L8, M18, N32, O21, P9, Q2
Electron configuration: 1s22s22p63s23p63d104s24p64d105s25p64f145d106s26p65f36d1 7s2
Phase: Solid
Melting point: 1405.3 K (1132.2 oC)
Boiling point: 4404 K (4131 oC)
Density: 19.1 g/cm3 (solid), 17.3 g/cm3 (Liquid at m.p)
Half Life(s): 1.41E+17
Lifetime(s): 2.03E+17
Decay mode: α decay
Neutron cross section (Barns): 7.57
Heat of fusion: 9.14 kJ/mol
Heat of vaporization: 417.1 kJ/mol
Molar hear capacity: 27.665 J/(mol∙K)
Thermal expansion: 0.0000139 K-1
Oxidation states: 6, 5, 4, 3, 2, 1
Ion charge: U6+, U4+
Electronegativity: Pauling scale: 1.38
Valence: (+2), +3, +4, (+5), +6
Ionization energies: 1st: 597.6 kJ/mol 2nd: 1420 kJ/mol
Atomic radius: 156 pm
Covalent radius: 196
Vander Waals radius: 186 pm
Crystal structure: Orthorhombic
Grid parameters: a=2.854 Å, b=5.870 Å, c=4.955 Å
Speed of sound thin rod: 3155 m/s
Thermal expansion: 13.9 μm/(m∙K)
Thermal conductivity: 27.5 W/(m∙K)
Electrical conductivity: 36×105
Electrical resistivity: 0.280 μΩ∙m
Super conducting point: 0.69 k (-272.46 oC)
Magnetic ordering: Paramagnetic
Volume magnetic susceptibility: 0.0004096
Mass magnetic susceptibility: 0.0000000215 m3/kg
Molar magnetic susceptibility: 0.000000005118
Young’s modulus: 208 GPa
Shear modulus: 111 GPa
Bulk modulus: 100 GPa
Poisson ratio: 0.23
Mohr hardness: 6
Vickers hardness: 1960 – 2500 MPa
Brinell hardness: 2350 – 3850 MPa
Molar volume: 0.000012495 m3/mol
CAS Number: 7440-61-1
Naming: After planet Uranus
Discovery: Martin Heinrich Klaproth (1789)
First isolation: Eugène-Melchior Péligot (1841)
Isotopes: 232U 233U 234U 235U 236U 238U
Uses: It is Used as Nuclear fuel to generate electricity in Nuclear power stations. Other synthetic transuranium elements are made with the help of Uranium. It is also used by the military to power nuclear submarines and in nuclear weapons.
Naturally occurring uranium is consists of 99% uranium-238 and 1% uranium-235. Uranium-235 is the only naturally occurring fissionable fuel (a fuel that can sustain a chain reaction). Uranium fuel used in nuclear reactors is enriched with uranium-235. The chain reaction is carefully controlled using neutron-absorbing materials.
The heat generated by the fuel is used to create steam to turn turbines and generate electrical power.
In a breeder reactor uranium-238 captures neutrons and undergoes negative beta decay to become plutonium-239. This synthetic, fissionable element can also sustain a chain reaction.
Depleted uranium is uranium that has much less uranium-235 than natural uranium. It is considerably less radioactive than natural uranium. It is a dense metal that can be used as ballast for ships and counterweights for aircraft and It is also used in ammunition and armour.
Biological role: Uranium is a toxic metal due to Radioactivity
Natural abundance: Uranium occurs naturally in several minerals such as uranite (pitchblende), brannerite and carnotite. It is also found in phosphate rock and monazite sands. World production of uranium is about 41,000 tonnes per year.
Abundance of Uranium 2×10-8%(In Universe), 1×10-7%(In Sun), 9.8×10-7(In Meteorites), 0.00018%(In Earth’s Crust), 3.3×10-7%(In Oceans), 1×10-7%(In Humans)
Extracted uranium is converted to the purified oxide, known as yellow-cake. Uranium metal can be prepared by reducing uranium halides with Group 1 or Group 2 metals, or by reducingsuranium oxides with calcium or aluminium.
#Uranium
