
Lanthanum (La) is a chemical element of the periodic table, located in the period 6, and has the atomic number 57. It is the first element in the lanthanide series. It is a soft, silvery-white metal, whose name comes from the Greek word “lanthanein”, which means to lie hidden. It is a highly reactive metal and is counted as one of the rare earth elements.
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– f block |
FAQs on Lanthanum Element
Lanthanum |
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‣ What does lanthanum look like? Appearance: silvery white |
‣ When was lanthanum discovered and by whom? Discovery: Carl Gustaf Mosander (1838) |
‣ Where is lanthanum found on the periodic table?![]() Location: Lanthanum is found in the sixth row of the periodic table, next to the barium element. |
‣ What is the atomic number of lanthanum? Atomic number (Z): 57 |
‣ What is the symbol of lanthanum? Symbol: La |
‣ What is the atomic weight of lanthanum? Standard atomic weight: 138.90547 |
‣ Lanthanum belongs to which block? Block: f-block |
‣ What period is lanthanum found? Period: 6 |
‣ What is the atomic radius of lanthanum? Atomic radius: empirical: 187 pm |
‣ Lanthanum covalent radius: 207±8 pm |
‣ What is the melting point of lanthanum? Melting point: 1193 K (920 °C, 1688 °F) |
‣ What is lanthanum boiling point? Boiling point: 3737 K (3464 °C, 6267 °F) |
‣ How many electron shells does lanthanum have? Electrons per shell: 2, 8, 18, 18, 9, 2 |
‣ What is the electron configuration for lanthanum? Electron configuration: [Xe] 5d1 6s2 |
‣ What is lanthanum ionization energy? Ionization energies: 1st: 538.1 kJ/mol 2nd: 1067 kJ/mol 3rd: 1850.3 kJ/mol |
‣ Is lanthanum a solid, liquid or gas? Phase (at r.t): solid |
‣ What is the density of lanthanum? Density (near r.t): 6.162 g/cm3 when liquid (at m.p): 5.94 g/cm3 |
‣ Lanthanum magnetic ordering: paramagnetic |
‣ Lanthanum natural occurrence: primordial |
‣ Oxidation state of lanthanum: +3 |
‣ Electronegativity for the element lanthanum Electronegativity: Pauling scale: 1.10 |
‣ Lanthanum poisson’s ratio: α form: 0.280 |
‣ Lanthanum heat of fusion: 6.20 kJ/mol |
‣ Lanthanum heat of vaporization: 400 kJ/mol |
‣ Lanthanum molar heat capacity: 27.11 J/(mol K) |
‣ Lanthanum molar magnetic susceptibility: +118.0 × 10-6 cm3/mol (298 K) |
‣ Speed of sound in lanthanum: 2475 m/s (at 20 °C) |
‣ What is the crystal structure of lanthanum? Crystal structure: double hexagonal close-packed (dhcp) |
‣ Thermal expansion of lanthanum: α, poly: 12.1 µm/(m.K) (at r.t) |
‣ Thermal conductivity of lanthanum: 13.4 W/(m.K) |
‣ Lanthanum electrical resistivity: α, poly: 615 nΩ.m (at r.t) |
‣ Lanthanum hardness Mohs hardness: 2.5 Vickers hardness: 360-1750 MPa Brinell hardness: 350-400 MPa |
‣ Young’s modulus of lanthanum: α form: 36.6 GPa |
‣ Shear modulus of lanthanum: α form: 14.3 GPa |
‣ Bulk modulus of lanthanum: α form: 27.9 GPa |
‣ Lanthanum CAS number: 7439-91-0 |
‣ Lanthanum vapor pressure
Vapor pressure (extrapolated) | ||||||
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P (Pa) | 1 | 10 | 100 | 1 k | 10 k | 100 k |
at T (K) | 2005 | 2208 | 2458 | 2772 | 3178 | 3726 |
‣ How many isotopes does lanthanum have?
Main isotopes of lanthanum | ||||
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Isotope | Abundance | Half-life (t1/2) | Decay mode | Product |
137La | syn | 6 × 104 y | ε | 137Ba |
138La | 0.089 % | 1.05 × 1011 y | ε β– | 138Ba 138Ce |
139La | 99.911 % | stable |
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