Rhenium

A Gist about Rhenium [Re] and its Discovery
Rhenium is a silvery-greyish chemical solid at the state of 20°C and has an atomic number of 75. This compound is present in the d-block, period 7, and 6th group in the Mendeleev’s Periodic Table. This is a transition metal in the 3rd of the table and is regarded asone of  the rarest elements to be found in the earth’s crust. Rhenium is denoted as [Re].

One of the interesting facts about its discovery is that Rhenium is the 2nd and last compound to be noted for a stable isotope. Except for Francium, the rest of the elements present in nature are all said to possess high radioactivity. The credits for the discovery goes to a Japanese chemist named ‘Masataka Ogawa’, who found the compound in 1908 and isolated the same in 1919. 

Also noting that Otto Berg, Walter Noddack, and Ida Noddack, are appreciated for Rhenium’s nomenclature in 1925. The element was named as “Rhenium” based on the major European River ‘Rhine’.

The Physical Properties of Rhenium 

  • The symbol of Rhenium is Re.

  • Regarded to be quite heavy. 

  • Ores of molybdenum and platinum are noted to have a minimal presence of Rhenium. But not available as a mineral characteristic.  

  • Next to Tungsten, the element Rhenium has the highest Melting point. 

  • Located at the d-block, 7th group, and 6th period in the Periodic Table.

  • Solid structure at the state of 20°C.

  • Possesses a low melting point. 

  • Silvery-greyish solid metal.

  • Hexagonal close packing (HCP) crystal structure. 

  • Good stability for high-temperature conditions. 

  • Rhenium is created by making use of the oxidised smelter residues that are derived when chemically processing the compound ‘molybdenite’. 

  • Extremely rare element to be found on earth. 

Pointing the Chemical Properties of Rhenium 

  • The electronic configuration is [Xe]4f14 5d5 6s2.

  • 75 is the atomic number of Rhenium.

  • 3185°C, 5765°F and 3458 K is the Melting point.

  • Atomic mass is 186.23 g.mol -1.

  • The Relative atomic mass is 186.207.

  • The Boiling point is 5590°C, 10094°F, and 5863 K.

  • 187Re is the Rhenium’s Key Isotope known. 

  • Third-row transition element. 

  • 20.8 g cm−3 is the density. 

Details on the Isotopes of Rhenium [Re]

Only 1 stable isotope is noted for Rhenium which is rhenium-185. Again, this is the rarest isotope ever and is sometimes observed in the metallic elements Tellurium and Indium. 

A total count of 33 isotopes are recognized for Rhenium, that ranges from 160Re to 194Re, all of them termed to be unstable and 183Re is the longest-present isotope among all with a half-life of 7- days. 

187Re and 185Re are the 2 unstable, naturally-occurring isotopes of Rhenium, yet have the longest half-life of approximately 1010 years.  The rhenium-186m is one of the key isotopes well-known for its longest metastable half-life of 200,000 years approximately. However, the state of ionic charges in the element majorly influences the half-life duration of these isotopes. 

As a notable point, the beta decay value of 187Re is effective during ore dating of rhenium–osmium and is found to be lowest in its available energy among all the other radionuclides present. The value is 2.6 keV.

The Important Rhenium Uses across Sectors

The uses of Rhenium are majorly noted in the domains of petroleum and the making of superalloys. Besides these, even fields such as photography, hydrogenation reactions and a few more areas make use of Rhenium. Let us learn the applications of Rhenium for all the mentioned cases and more from the following. 

  • Rhenium acts as a superalloy for the high-temperature gas turbine engines such as CMSX-4 (2nd gen) and CMSX-10 (3rd gen) respectively. 

  • This element is notable for amplifying the strength of high-temperature, similar to other nickel-based superalloys present. This is possible as Rhenium improves the creep strength of the element added with it.  

  • Tungsten-Rhenium wires are manufactured to develop a wiring system that is high on ductility even after the recrystallization processes. The same is used as ‘thermocouples’ for temperature measurements, up to the range of 2200 °C.

  • The undesirable phases of TCP (topologically close-packed) unstable microstructures are caused when Rhenium reacts with certain superalloys.

  • Rhenium plays a major role in the photoflash aspect of photography. 

  • In the production of lamps and filaments, tungsten and molybdenum are added with Rhenium to form the needed alloy.

  • Rhenium-Platinum alloys are good catalytic reformers to achieve high-octane liquid products. 

  • The use of Rhenium transition metal as a superalloy is also observed in the case of making high-temperature parts of a jet. Above the average level of jet parts production is possible due to Rhenium and its properties.

  • Apart from being an additive for molybdenum and tungsten, this compound is also preferred in hydrogenation fine chemicals. 

Conclusion 

Rhenium is a silvery-grey solid chemical structure, classified in the 7th group and 6th period of the d-block in the periodic table and noted to be a transition metal. This element was discovered by a Japanese chemist in 1908, and 1919 was the year of isolation. This element is both good concerning its high-temperature stability and low melting points. The rhenium-185 is the rarest, unstable and naturally-occurring key isotope of Rhenium. The Rhenium uses are observed in an array of domains including, lamp production, superalloys, hydrogenation chemical reactions, catalytic procedures, gas turbine making, and even in the production of jet parts. 

FAQ (Frequently Asked Questions)

1. How are the Compounds of Rhenium available outside with their Oxidation States?

Rhenium is commercially sold frequently with the oxidation states of  +7, +6, +4, and +2. The oxidation states of Rhenium range from − 3 to + 7, except - 2. It owes to a sizable difference in the number of valence electrons in their respective shells). The white Perrhenates, specifically ammonium and sodium, are the ionic compounds of Rhenium and are also commercially present with the mentioned two soluble elements.

2. Mention a Few Lines about the Primordial Occurrence of Rhenium on Earth?

Rhenium is a key transition metal that is said to be the rarest on earth. It is estimated that about a concentration of 1 ppb (on average) is present in the earth’s crust. Some quotes refer to the Primordial abundance of Rhenium on earth as 0.5 ppb and making it the ‘77th common element’ present in the earth’s crust. This chemical element is however not found in the free state in the natural ecosystem. 

3. Give the Young’s, Shear, and Bulk’s Modulus Values for Rhenium with its Poisson Ratio as Well.

The Young’s Modulus is 463 GPa, and 178 GPa is the Shear’s Modulus. Rhenium’s Bulk Even though present widely in the surrounding ecosystem, Rhenium [Re] is one of the rarely-derivable chemical substances on earth. Present in the d-block and group 7 of the periodic table, Rhenium has an important role in diverse fields of work and research, including petroleum, chemical reactions, photography, etc. This is an interesting read and with no further delay, let us understand the basic information about the physical and chemical properties, a few facts, and the Rhenium uses along with data about its available isotopes and measures followed during application as superalloy. 

4. Who are the Top 3 Reserve Holders and Top 4 Producers of the Transition Element Rhenium in this World?

The Top 3 Reserve Holders of Rhenium are Russia, Chile and the United States of America. Again Chile and the United States of America with Poland and Kazakhstan are regarded to be the Top 3 Producers of Rhenium in this world. Even imports are majorly noted from the USA and Germany. 

5. What are the Health and Safety Measures of Rhenium’s Usage?

The safety hazards of using Rhenium are incomplete on-field. Scholars recommend using this element with proper caution since the level of toxicity is not to be assumed as safe. On the other side, the soluble salts of this compound similar to the perrhenates and rhenium halides are hazardous to species. But still, no evidence if the toxicity is because of Rhenium Is present or the other two elements.