Hf

Hafnium

Identification

CAS Number: 7440-58-6

Discovery Year: 1923

Discoverer: Dirk Coster, Georg von Hevesy

Discovery Location: Denmark

Properties

Atomic Mass: 178.49 →Density: 13.3 g/cm³ →

Crust Abundance: 3 mg/kg

Crystal Structure: HEX

Atomic Dimensions

Atomic Radius: 155 pm →

Atomic Radius (Rahm): 264 pm

Covalent Radius: 175 pm →

Van der Waals Radius: 223 pm

Metallic Radius: 144 pm

Atomic Volume: 13.6 cm³/mol

Lattice Constant: 3.2 Å

Thermodynamics

Melting Point: 2503 K →Boiling Point: 5470 K →Specific Heat: 0.146 J/(g·K) →Thermal Conductivity: 23 W/(m·K) →Heat of Fusion: 25.1 kJ/mol →Heat of Vaporization: 575 kJ/mol →

Heat of Formation: 618.4 kJ/mol

Electronic Structure

Electron Config: [Xe] 4f14 5d2 6s2

Block: d

Period: 6 →Group: 4 →Electronegativity: 1.3 →Electron Affinity: 0.013999999999999999 eV →

Oxidation States: +4

Abundance & Geochemistry

Crust Abundance: 3 mg/kg

Sea Abundance: 0.000007000000000000001 mg/L

Geochemical Class: high field strength

Goldschmidt Class: litophile

About

Silvery lustrous metallic transition element. Used in tungsten alloys in filaments and electrodes, also acts as a neutron absorber. First reported by Urbain in 1911, existence was finally established in 1923 by D. Coster, G.C. de Hevesy in 1923.

Isotopes

Hf-180 180 35.08%

Hf-178 178 27.28%

Hf-177 177 18.60%

Hf-179 179 13.62%

Hf-176 176 5.26%

Hf-174 174 0.1600%