""Sample Rmz-040 is a sample from the green mafic dyke with quartz, and contains a silvery metallic mineral (Molybdenite?) up to 4 mm diameter in places. "" Intresting and very expensive stuff Sample Rmz-040 is a sample from the green mafic dyke with quartz, and contains a silvery metallic mineral (Molybdenite?) up to 4 mm diameter in places. ........... price exceeding US$6,000 per kilogram, as of 2009
.... RheniumFrom Wikipedia, the free encyclopediaJump to: navigation, search
tungsten ? rhenium ? osmium
Tc
?
Re
?
Bh
75RePeriodic table
Appearance
grayish white
General properties
Name, symbol, number rhenium, Re, 75
Pronunciation /'ri?ni?m/ REE-nee-?m
Element category transition metal
Group, period, block 7, 6, d
Standard atomic weight 186.207g·mol-1
Electron configuration [Xe] 4f14 5d5 6s2
Electrons per shell 2, 8, 18, 32, 13, 2 (Image)
Physical properties
Phase solid
Density (near r.t.) 21.02 g·cm-3
Liquid density at m.p. 18.9 g·cm-3
Melting point 3459 K, 3186 °C, 5767 °F
Boiling point 5869 K, 5596 °C, 10105 °F
Heat of fusion 60.43 kJ·mol-1
Heat of vaporization 704 kJ·mol-1
Specific heat capacity (25 °C) 25.48 J·mol-1·K-1
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 7, 6, 5, 4, 3, 2, 1, 0, -1
(mildly acidic oxide)
Electronegativity 1.9 (Pauling scale)
Ionization energies
(more) 1st: 760 kJ·mol-1
2nd: 1260 kJ·mol-1
3rd: 2510 kJ·mol-1
Atomic radius 137 pm
Covalent radius 151±7 pm
Miscellanea
Crystal structure hexagonal
Magnetic ordering paramagnetic[1]
Electrical resistivity (20 °C) 193 nO·m
Thermal conductivity (300 K) 48.0 W·m-1·K-1
Thermal expansion 6.2 µm/(m·K)
Speed of sound (thin rod) (20 °C) 4700 m/s
Young's modulus 463 GPa
Shear modulus 178 GPa
Bulk modulus 370 GPa
Poisson ratio 0.30
Mohs hardness 7.0
Vickers hardness 2450 MPa
Brinell hardness 1320 MPa
CAS registry number 7440-15-5
Most stable isotopes
Main article: Isotopes of rhenium
iso NA half-life DM DE (MeV) DP
185Re 37.4% 185Re is stable with 110 neutrons
187Re 62.6% 4.12×1010 y a (not observed) 1.653 183Ta
ß- 0.0026 187Os
v • d • e
Rhenium (pronunciation: /'ri?ni?m/ REE-nee-?m) is a chemical element with the 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 average concentration of 1 part per billion (ppb), rhenium is one of the rarest elements in the Earth's crust. The free element has the third-highest melting point of any element, exceeded only by tungsten and carbon. Rhenium resembles manganese chemically and is obtained as a by-product of molybdenum and copper refinement. Rhenium shows in its compounds a wide variety of oxidation states ranging from -1 to +7.
Discovered in 1925, rhenium was the last naturally occurring stable element to be discovered (francium was the last identified naturally occurring element, but it is unstable). Rhenium was named after the river Rhine.
Nickel-based superalloys for use in jet engines contain up to 6% of rhenium, making jet engine construction the largest use for the element, with chemical industry catalytic uses being next-most important. Because of the low availability relative to demand, rhenium is among the most expensive industrial metals, with an average price exceeding US$6,000 per kilogram, as of 2009.
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