Lanthanum
Lanthanum General
Name:Lanthanum | Symbol:La |
Type:Transition Metal | Atomic weight:138.9055 |
Density @ 293 K:6.16 g/cm3 | Atomic volume:22.5 cm3/mol |
Discovered:
Lanthanum was discovered by Carl G. Mosander in 1839 as the oxide (lanthana) in the mineral cerite. The element name comes from the Greek word 'lanthano', meaning to be hidden. |
Lanthanum States
State (s, l, g):solid | |
Melting point:1193.2 K (920 °C) | Boiling point:3733 K (3460 °C) |
Lanthanum Energies
Specific heat capacity: 0.19 J g-1 K-1 | Heat of atomization:414 kJ mol-1 |
Heat of fusion: 6.20 kJ mol-1 | Heat of vaporization : 400 kJ mol-1 |
1st ionization energy: 538.1 kJ mol-1 | 2nd ionization energy:1067 kJ mol-1 |
3rd ionization energy:1850 kJ mol-1 | Electron affinity:50 kJ mol-1 |
Lanthanum Oxidation & Electrons
Shells: 2,8,18,18,9,2 | Electron configuration:[Kr] 5d1 6s2 |
Minimum oxidation number:0 | Maximum oxidation number:3 |
Min. common oxidation no.:0 | Max. common oxidation no.:3 |
Electronegativity (Pauling Scale):1.1 | Polarizability volume:31.1 Å3 |
Lanthanum Appearance & Characteristics
Structure:hcp (hexagonal close-packed) | Color:silvery-white |
Hardness:2.5 mohs | |
Harmful effects:
Lanthanum and its compounds are considered to be moderately toxic. |
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Characteristics:
Lanthanum is a silvery-white soft metal, which can be cut with a knife. It is ductile, malleable and exposed surfaces tarnish rapidly in air forming the oxide. Lanthanum reacts with water to form lanthanum hydroxide plus hydrogen gas. Lanthanum is chemically reactive and forms compounds with carbon, nitrogen, boron, selenium, silicon, phosphorus, sulfur, and with the halogens. Uses: Lanthanum is used in large quantities in batteries for hybrid automobiles. It is used as an additive to make nodular cast iron and as an additive in steel. Lanthanum is used in hydrogen sponge alloys, which take up to 400 times their own volume of hydrogen gas. It is also used in flame lighter flints. Lanthanum compounds are widely used in carbon lighting applications such as for studio lighting and projection. Lanthanum oxide (La2O3) is used to make camera and telescope lenses. |
Lanthanum Reactions
Reaction with air:vigorous, w/ht ⇒ La2O3 | Reaction with 6 M HCl:mild, ⇒ H2, LaCl3 |
Reaction with 15 M HNO3:mild, ⇒ La(NO3)3 | Reaction with 6 M NaOH: |
Lanthanum Compounds
Oxide(s):La2O3 | Chloride(s):LaCl3 |
Hydride(s):LaH2, LaH3 |
Lanthanum Radius
Atomic radius:195 pm | Ionic radius (1+ ion):pm |
Ionic radius (2+ ion):pm | Ionic radius (3+ ion):117.2 pm |
Ionic radius (2- ion):pm | Ionic radius (1- ion):pm |
Lanthanum Conductivity
Thermal conductivity:13.4 W m-1 K-1 | Electrical conductivity: 1.9 x 106 S m-1 |
Lanthanum Abundance & Isotopes
Abundance earth's crust:34 parts per million by weight, 5 parts per million by moles | |
Abundance solar system:2 parts per billion by weight, 0.01 parts per billion by moles | |
Cost, pure:$233 per 100g | |
Cost, bulk:per 100g | |
Source:
Lanthanum is not found free in nature. It is found mainly in the minerals monazite and bastnasite. Commercially, it is recovered from monazite sand and bastnasite using various complex extraction techniques. Pure lanthanum is obtained by the reduction of the flouride with calcium metal. |
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Isotopes:
Lanthanum has 31 isotopes whose half-lives are known, with mass numbers 119 to 150. Of these, one is stable, 139La. |
Lanthanum Other
Other:
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