Lanthanum

Lanthanum is a soft, ductile, silvery-white metallic element that tarnishes when exposed to air, forming a dull coating. Lanthanum is the eponymous member of the lanthanide series and is used in specialty glass, camera lenses, and carbon-arc lighting. It is also used as a catalyst for petroleum refining.

Overview

English Name:

Lanthanum

Latin Name:

Lanthanum

Year Discovered:

1839

Discovered By:

Carl Gustav Mosander

Group:

Period:

Electrons:

CAS Number:

7439-91-0

Cost Per 100 Grams:

$50

Atomic Properties

Electronic Configuration:

[Xe] 5d¹ 6s²

Ion Charge:

Ionisation Energies:

538.1 kJ/mol

Atomic Radius (Empirical):

187 pm

Atomic Radius (Calculated):

219 pm

Covalent Radius:

169 pm

Van Der Waals Radius:

N/A

Ionisation Potential of An Atom:

5.58 eV

Electrons Per Layer:

2, 8, 18, 18, 9, 2

Atomic Multiplicities Of The Gas:

Atomic Weight:

138.91

Oxidation States

Reactivity

Electron Affinity:

50 kJ/mol

Valence:

Electronegativity:

1.1

Thermal Properties

Melting Point:

920°C

Boiling Point:

3464°C

Critical Point:

Pressure: N/A

Temperature: N/A

Thermal Conductivity:

0.135 W/(m·K)

Heat Capacity:

Specific: 0.195 J/(g·K)

Molar: 27.1 J/(mol·K)

Thermal Coefficient:

0.000011

Enthalpy:

Fusion: 6.2 kJ/mol

Vaporisation: 400 kJ/mol

Atomization: 431 kJ/mol

Curie Temperature:

N/A

Neel Temperature:

N/A

Superconductivity Point:

N/A

Physical and Chemical Properties

State of matter (25° C/ 77°F):

Solid

Density:

Solid: 6.17 g/cm³

Molar Volume (Vmol):

22.5 cm³/mol

Speed of Sound (Vs):

2475 m/s

Hardness:

2.5

Bulk Modulus (K):

28 GPa

Shear Modulus (G):

N/A

Young's Modulus (E):

N/A

Color:

Silvery-white

Brinell Hardness (MPa):

N/A

Liquid Density (Kg/m^3):

6.15 kg/m³

Hardness of Mohs:

2.5

Refractive Index:

N/A

Vickers Hardness (MPa):

N/A

Crystal Structure:

Hexagonal close-packed

Electromagnetic Properties

Electrical Type:

Conductor

Resistivity:

5.9 × 10^-6 Ω·m

Magnetic Type:

Paramagnetic

Superconductivity:

Not applicable

Volume Magnetic Susceptibility:

1.0 × 10^-5

Mass Magnetic Susceptibility:

1.6 × 10^-6 m³/kg

Molar Mass Susceptibility:

2.2 × 10^-4 m³/mol

Electrical Conductivity:

1.7 × 10^5 S/m

Mass (γ_mass):

1.0 × 10^-25 kg

Mass (γ_mol):

1.0 × 10^-22 mol

Volume (γ_vol):

22.5 L

Grid Parameters

Crystal Structure:

Hexagonal close-packed

Grid Parameters:

a = 3.75 Å, c = 6.04 Å

Attitude:

N/A

Debye Temperature:

N/A

Safety and Precautions

Signal Word:

Warning

Hazard Statements:

H250, H260, H315, H319, H335

Precautionary Statements:

P223, P231 + P232, P261, P305 + P351 + P338

RTECS Number:

Not available

Risk:

Flammability: Pyrophoric
Health Risk: Irritant
Reactivity: Reacts with water
Specific Risk: None

Importance

Main sources:

Minerals, mining

Main Usage:

Specialty glass, camera lenses, carbon-arc lighting, catalysts

Nuclear Properties

Radioactive:

Isotopes:

La-139

Neutron Cross Sectional:

8.9 barns

Half Life (s):

None

Lifetime:

Stable

Prevalence

Universe:

0.0006%

Sun:

0.0006%

Oceans:

0.00000001%

Humans:

0.00000001%

Earth's Crust:

0.0018%

Meteorites:

0.0002%