75
Re
Rhenium
186
Rhenium (Re)
Transition MetalGroup 7Period 6d-block-block
Rhenium is a chemical element with symbol Re and atomic number 75. It is a silvery-white, heavy, third-row transition metal in group 7 of the periodic table. With an estimated average concentration of 1 part per billion (ppb), rhenium is one of the rarest elements in the Earth's crust.
Latin name: Rhenium
Atomic Number
75
Atomic Mass
186 g/mol
Phase (STP)
Solid
Electron Config.
[Xe] 4f¹⁴ 5d⁵ 6s²
General
SymbolRe
Atomic Number75
Atomic Mass186 g/mol
CategoryTransition Metal
Group7
Period6
Blockd-block
Electron Configuration[Xe] 4f¹⁴ 5d⁵ 6s²
Valence Electrons7
Coloursilvery-white metallic
Appearancesilvery-grayish
CAS NumberCAS7440-15-5
Physical Properties
Phase (STP)Solid
Density21.02 g/cm³
Melting Point3185.85°C · 5766.53°F · 3459.00 K
Boiling Point5595.85°C · 10104.53°F · 5869.00 K
Atomic Properties
Atomic Radius217 pm
Electronegativity1.9 Pauling
Ionization Energy760 kJ/mol
Oxidation States+7, +6, +4
Ion ChargeRe4+/Re6+/Re7+
Thermodynamic
Molar Heat25.48 J/(mol·K)
Crystal Structure
Crystal Structurehexagonal close-packed
Mechanical Properties
Mohs Hardness7
Nuclear & Hazards
Half-lifestable (naturally occurring isotope Re-185 is stable)
Abundance
In Universe0.000002%
In Sun0.0000015%
In Earth's Crust0.000004%
Discovery & History
Discovery Year1925
Discovered ByWalter Noddack, Ida Noddack, Otto Berg
Country of DiscoveryGermany
Named ByWalter Noddack
Isotopes of Rhenium
| Isotope | Abundance | Half-life | Decay |
|---|---|---|---|
| Re-185 | 37.4% | Stable | — |
| Re-187 | 62.6% | 4.12 × 10¹⁰ years | β⁻ |