What Is Rhenium?
Rhenium, symbol Re and atomic number 75, belongs to the transition metals — the wide central block known for hardness and multiple oxidation states.
One of the rarest elements. Has the highest boiling point of all elements.
As a transition metal in Period 6 and Group 7 (Transition Metals), rhenium's placement on the table reflects its electron configuration of [Xe] 4f¹⁴ 5d⁵ 6s², which governs its bonding behavior and the type of compounds it typically forms.
Position on the Periodic Table
Rhenium is located in Period 6, an unusually long row that includes the entire lanthanide series.
Within that row, rhenium sits in Group 7 (Transition Metals), alongside elements that share a similar number of valence electrons and, by extension, similar chemical behavior.
This position is not arbitrary — the periodic table was deliberately organized so that an element's row and column reveal its expected reactivity, bonding pattern, and physical state at a glance.
Physical & Chemical Properties
Rhenium has an atomic mass of 186.207 u and a density of 21.02 g/cm³. Its melting point is 3186°C and its boiling point is 5596°C.
Rhenium is malleable and ductile in its pure metallic form, and like other transition metals it can typically form more than one stable oxidation state.
Electron Configuration Explained
Rhenium's electron configuration is [Xe] 4f¹⁴ 5d⁵ 6s², describing how its electrons are distributed across shells and subshells around the nucleus.
Reading the configuration in order shows electrons filling shells of increasing energy, following the standard Aufbau principle that explains how atomic structure builds up across the periodic table.
The outermost (valence) electrons shown in this configuration are what ultimately determine rhenium's chemical reactivity and the type of bonds it forms with other elements.
History & Discovery
Rhenium was formally discovered in 1925, Noddack, identified through the careful isolation and analytical techniques typical of that era's chemical research.
Many elements from this period were anticipated by Dmitri Mendeleev's periodic table, which successfully predicted gaps corresponding to undiscovered elements well before laboratory instruments existed to confirm them directly.
What Is Rhenium Used For?
Rhenium's specific properties make it useful in several applications, including:
- Jet engine turbine blades
- Catalysts
- Electrical contacts
- Thermocouples
- Filaments
These uses reflect rhenium's underlying classification as a transition metal, since the same properties that define its category in chemistry also determine where it becomes practically useful.
Fun Facts About Rhenium
- Rhenium was one of the last naturally occurring elements to be discovered, in 1925.
- Rhenium is element number 75 on the periodic table, in Period 6 and Group 7.
- Its standard atomic mass is 186.207 u, calculated from the natural abundance of its isotopes.
Frequently Asked Questions
What is Rhenium's atomic number?
Rhenium has atomic number 75.
What is Rhenium's chemical symbol?
Rhenium's symbol is Re.
What group and period is Rhenium in?
Rhenium is in Period 6, Group 7 (Transition Metals).
What is Rhenium's atomic mass?
Rhenium's standard atomic mass is 186.207 u.