R

Rhenium

IUPAC: Rhenium

Re Elements CAS 7440-15-5
Quick Reference
Formula / NotationRe
CAS Number7440-15-5
Molecular Weight186.21
Melting Point3186.0
Boiling Point5596.0
Density21.04
SolubilityInsoluble in water
AppearanceDense, silvery-grey, lustrous metal
Also Known AsRe, rhenium metal
CategoryElements

What is Rhenium?

Rhenium is a dense, silvery-grey transition metal, atomic number 75. One of the rarest elements in Earth crust. Has the second highest melting point after tungsten. Critical component of nickel-based superalloys for jet engine turbine blades.

Formula & Notation

Re

IUPAC Name: Rhenium

Other Names / Synonyms: Re, rhenium metal

Properties & Characteristics

Atomic number: 75. Atomic mass: 186.21 g/mol. Period 6, Group 7. Melting point: 3186 C (second highest). Boiling point: 5596 C. Density: 21.04 g/cm3. Electronegativity: 1.90. Oxidation states: -1 to +7. Two stable isotopes: Re-185 (37.4%) and Re-187 (62.6%, weakly radioactive).

Physical Data

PropertyValue
Melting Point3186.0
Boiling Point5596.0
Density21.04
Molecular Weight186.21
SolubilityInsoluble in water
AppearanceDense, silvery-grey, lustrous metal

Uses & Applications

Nickel superalloy additive for jet turbine blades (single-crystal turbine blades contain up to 6% Re). Platinum-rhenium catalysts for petroleum reforming. Filaments in mass spectrometers and ion gauges. Re-186 and Re-188 for cancer radiotherapy. Thermocouples (W-Re).

Safety Information

Rhenium metal: low acute toxicity. Rhenium compounds: moderate toxicity. Rhenium oxide dust: irritant. Re-186, Re-188: radioactive beta emitters - radiation precautions. Very expensive metal - handle carefully to avoid waste.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Rhenium
Formula Re
CAS Number 7440-15-5
Molecular Weight 186.21
Category Elements
Synonyms Re, rhenium metal

Frequently Asked Questions

Rhenium is a dense, silvery-grey transition metal, atomic number 75. One of the rarest elements in Earth crust. Has the second highest melting point after tungsten. Critical component of nickel-based superalloys for jet engine turbine blades.

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