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Lanthanum
Chemical Properties & Compounds
| Symbol | Atomic Number | Atomic Weight | Melting Point | Boiling Point | Phase | Density | Classification |
| La | 57 | 138.90547 | 920 °C | 3464 °C | Solid | 6.162 g/cm3 | Metal |
|
|
|
| General |
| Name, Symbol, Number |
lanthanum, La, 57 |
| Chemical series |
lanthanides |
| Group, Period, Block |
3, 6, f |
| Appearance |
silvery white
 |
| Standard atomic weight |
138.90547(7) g·mol−1 |
| Electron configuration |
[Xe] 5d1 6s2 |
| Electrons per shell |
2, 8, 18, 18, 9, 2 |
| Physical properties |
| Phase |
solid |
| Density (near r.t.) |
6.162 g·cm−3 |
| Liquid density at m.p. |
5.94 g·cm−3 |
| Melting point |
1193 K
(920 °C, 1688 °F) |
| Boiling point |
3737 K
(3464 °C, 6267 °F) |
| Heat of fusion |
6.20 kJ·mol−1 |
| Heat of vaporization |
402.1 kJ·mol−1 |
| Heat capacity |
(25 °C) 27.11 J·mol−1·K−1 |
Vapor pressure (extrapolated)
| P(Pa) |
1 |
10 |
100 |
1 k |
10 k |
100 k |
| at T(K) |
2005 |
2208 |
2458 |
2772 |
3178 |
3726 |
|
| Atomic properties |
| Crystal structure |
hexagonal |
| Oxidation states |
3
(strongly basic oxide) |
| Electronegativity |
1.10 (scale Pauling) |
Ionization energies
(more) |
1st: 538.1 kJ·mol−1 |
| 2nd: 1067 kJ·mol−1 |
| 3rd: 1850.3 kJ·mol−1 |
| Atomic radius |
195 pm |
| Covalent radius |
169 pm |
| Miscellaneous |
| Magnetic ordering |
? |
| Electrical resistivity |
(r.t.) (α, poly) 615 nΩ·m |
| Thermal conductivity |
(300 K) 13.4 W·m−1·K−1 |
| Thermal expansion |
(r.t.) (α, poly)
12.1 µm/(m·K) |
| Speed of sound (thin rod) |
(20 °C) 2475 m/s |
| Young's modulus |
(α form) 36.6 GPa |
| Shear modulus |
(α form) 14.3 GPa |
| Bulk modulus |
(α form) 27.9 GPa |
| Poisson ratio |
(α form) 0.280 |
| Mohs hardness |
2.5 |
| Vickers hardness |
491 MPa |
| Brinell hardness |
363 MPa |
| CAS registry number |
7439-91-0 |
| Selected isotopes |
|
|
| References |
|
Lanthanum Compounds
|
Source: Wikipedia article Lanthanum
|
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Chemistry Quick Facts
