Rhenium

Rhenium, ₇₅Re

Rhenium
Pronunciation	/ˈriːniəm/ ​(REE-nee-əm)
Appearance	silvery-grayish
Standard atomic weight Ar°(Re)
	186.207±0.001[1] 186.21±0.01 (abridged)[2]
Rhenium in the periodic table
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson Tc ↑ Re ↓ Bh tungsten ← rhenium → osmium
Atomic number (Z)	75
Group	group 7
Period	period 6
Block	d-block
Electron configuration	[Xe] 4f14 5d5 6s2
Electrons per shell	2, 8, 18, 32, 13, 2
Physical properties
Phase at STP	solid
Melting point	3459 K ​(3186 °C, ​5767 °F)
Boiling point	5903 K ​(5630 °C, ​10,170 °F)
Density (at 20° C)	21.010 g/cm3 [3]
when liquid (at m.p.)	18.9 g/cm3
Heat of fusion	60.43 kJ/mol
Heat of vaporization	704 kJ/mol
Molar heat capacity	25.48 J/(mol·K)
Vapor pressure P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 3303 3614 4009 4500 5127 5954
Atomic properties
Oxidation states	−3, −1, 0, +1, +2, +3, +4, +5, +6, +7 (a mildly acidic oxide)
Electronegativity	Pauling scale: 1.9
Ionization energies	1st: 760 kJ/mol 2nd: 1260 kJ/mol 3rd: 2510 kJ/mol (more)
Atomic radius	empirical: 137 pm
Covalent radius	151±7 pm
Spectral lines of rhenium
Other properties
Natural occurrence	primordial
Crystal structure	​hexagonal close-packed (hcp) (hP2)
Lattice constants	a = 276.10 pm c = 445.84 pm (at 20 °C)[3]
Thermal expansion	5.61×10−6/K (at 20 °C)[a]
Thermal conductivity	48.0 W/(m⋅K)
Electrical resistivity	193 nΩ⋅m (at 20 °C)
Magnetic ordering	paramagnetic[4]
Molar magnetic susceptibility	+67.6×10−6 cm3/mol (293 K)[5]
Young's modulus	463 GPa
Shear modulus	178 GPa
Bulk modulus	370 GPa
Speed of sound thin rod	4700 m/s (at 20 °C)
Poisson ratio	0.30
Mohs hardness	7.0
Vickers hardness	1350–7850 MPa
Brinell hardness	1320–2500 MPa
CAS Number	7440-15-5
History
Naming	after the river Rhine (German: Rhein)
Discovery	Masataka Ogawa (1908)
First isolation	Masataka Ogawa (1919)
Named by	Walter Noddack, Ida Noddack, Otto Berg (1925)
Isotopes of rhenium v e
Main isotopes[6] Decay abun­dance half-life (t1/2) mode pro­duct 185Re 37.4% stable 186Re synth 3.7185 d β− 186Os ε 186W 186mRe synth 2×105 y IT 186Re β− 186Os 187Re 62.6% 4.12×1010 y β− 187Os
Category: Rhenium view talk edit | references

Rhenium is a chemical element; it has symbol Re and atomic number 75. It is a silvery-gray, 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. It has the third-highest melting point and second-highest boiling point of any element at 5869 K.^[7] It resembles manganese and technetium chemically and is mainly obtained as a by-product of the extraction and refinement of molybdenum and copper ores. It shows in its compounds a wide variety of oxidation states ranging from −1 to +7.

Rhenium was originally discovered by Masataka Ogawa in 1908, but he mistakenly assigned it as element 43 rather than element 75 and named it nipponium. It was rediscovered by Walter Noddack, Ida Tacke and Otto Berg in 1925,^[8] who gave it its present name. It was named after the river Rhine in Europe, from which the earliest samples had been obtained and worked commercially.^[9]

Nickel-based superalloys of rhenium are used in combustion chambers, turbine blades, and exhaust nozzles of jet engines. These alloys contain up to 6% rhenium, making jet engine construction the largest single use for the element. The second-most important use is as a catalyst: it is an excellent catalyst for hydrogenation and isomerization, and is used for example in catalytic reforming of naphtha for use in gasoline (rheniforming process). Because of the low availability relative to demand, it is expensive, with price reaching an all-time high in 2008/2009 of US$10,600 per kilogram (US$4,800 per pound). Due to increases in recycling and a drop in demand for rhenium in catalysts, the price had dropped to US$2,844 per kilogram (US$1,290 per pound) as of July 2018.^[10]

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