Lanthanum
Chemical, physical and material properties and data of the chemical element Lanthanum.
General Information about Lanthanum
Regular nameLanthanumChemical symbolLaOther namesSystematic nameHistorical namesName meaning, originDiscovery (year)OccurencePosition in the PSEGroup membership
Atomar Properties of Lanthanum
Atomic number Z57 = number of protonsStandard Atomic Weight138.90547 (7)
Electron configuration of Lanthanum
| 1s | 2s | 2p | 3s | 3p | 3d | 4s | 4p | 4d | 4f | 5s | 5p | 5d | 5f | 6s | 6p | 6d | 6f | 7s | 7p |
|---|
| 2 | 2 | 6 | 2 | 6 | 10 | 2 | 6 | 10 | | 2 | 6 | 1 | | 2 | | | | | |
Abbreviated form: [Xe] 5d1 6s2 .
Ionization Energies of Lanthanum
The following table lists the ionization energies IE (ionization potentials); the IE is the energy required in electron volts (eV) per atom to separate a given electron from an Lanthanum atom.
| IE1 | IE2 | IE3 | IE4 | IE5 |
|---|
| 5.5769 | 11.059 | 19.1774 | 49.95 | 61.6 |
Isotopic Data of Lanthanum
An overview of the nuclides as well as the isotopic data and properties are listed on the following page: Lanthanum isotopes.
Chemistry of Lanthanum
Oxidation states+ 3Electronegativity1.1 (Pauling original)
1.10 (Pauling)
1.09 (Allen)
0.92 (Sanderson)
1.08 (Allred-Rochow)
3.1 eV (Pearson)Electron affinity0.55(2) eV
53(2) kJ mol-1
Standard Electrode Potential
| E0 (V) | Symbol | Nox | Name Ox.
Name Red. | Ox.
Red. | e- |
|---|
| -2.9 | La | + III
0 | Lanthanum hydroxide
Lanthanum | La(OH)3
⇄ La (s) + 3 OH- | + 3 e- |
| -2.379 | La | + III
0 | Lanthanum(III) cation
Lanthanum | La3+
⇄ La (s) | + 3 e- |
Material and Physical Properties
Melting point920 °CEnthalpy of fusion (molar)6.20 kJ mol-1Boiling point3464 °CEnthalpy of vaporization399.6 kJ mol-1Density6.162 g cm-3
External Data, Identifiers
CAS registry number7439-91-0InChI =1S/LaInChIKeyFZLIPJUXYLNCLC-UHFFFAOYSA-NPubChem ID23926
Last update: 2022-12-12
Perma link: https://www.chemlin.org/chemical-elements/lanthanum.php
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