Element

Rhenium Element Properties and Information

September 6, 2022

Rhenium Element Properties and Information

Rhenium is 75^th element on the periodic table. Elements are arranged in the periodic table on the basis of the atomic number. Atomic number is the number of protons in the nucleus of the atom. Rhenium has an atomic number of 75. It is located in the Group 7 and Period 6 of the periodic table of elements. It is denoted by ‘Re’. Its name is derived from ‘Rhenus’ which is a Latin name for the ‘Rhine’ river.

In 1905, Masataka Ogawa was investigating a mineral from Sri-lanka called Thorianite, and from the spectral lines in its atomic spectra he claim that there is new element within it and its placement is below the manganese. His claim was tested and refuted, however, many years later it was found that the new element which Ogawa talked about could be placed below the position he claimed. At that time both of the elements below manganese were unknown; these elements were technetium and rhenium, placed one below another respectively. Walter Noddack and Ida Tacke isolated rhenium in 1925; they found it as an impurity in Gadolinite. Rhenium is never found in nature in uncombined form, it is the last element on the periodic table, in sequence, to occur naturally and have a non-radioactive form. It is amongst the rarest element on Earth and it is widely distributed throughout the Earth’s crust, although only amounting to 0.001 ppm.

Physical Properties

Rhenium is a heavy metal which has silvery-gray appearance and finds its place in the third transition series.
The atomic mass of rhenium is 186.23.
The melting point of rhenium is 3170°C.
The boiling point of rhenium is 5627°C.
The density of rhenium is 20500 in S.I. units at 20°C.
Rhenium has second highest melting point among all metals, it is second only to tungsten.
Naturally occurring rhenium has one stable isotope and one unstable isotope. Rhenium-185 is the stable isotope and rhenium-186 is the unstable isotope.

Chemical Properties

Rhenium compounds display all the oxidation states ranging from -3 to +7 except for -2.
Rhenium is observed to form halides, oxides, oxyhalides, sulfides, boride, and variety of organometallic compounds.

Methods of Production

From Molybdenum deposits: About 80% of rhenium produced worldwide comes from porphyry molybdenum deposits. The ores are crushed, pre-processed and then roasted to volatilize rhenium oxide. Rhenium(VII) oxide and perrhenic acid are leached from flue dusts and gases using water. They are precipitated as perrhenate salts and further purified using recrystalization. The rhenium metal is obtained by reducing ammonium perrhenate with hydrogen at high temperatures.

Relevance in Chemical and Related Industries

Alloys: Addition of rhenium in alloys improves the creep strength.
Catalysts: Rhenium is used in catalytic-reforming process in the form of rhenium-platinum alloy.