Element 77
Iridium
Transition metals
Iridium (Ir) is in the d-block of the periodic table — group 9, period 6.
Iridium is a chemical element with symbol Ir and atomic number 77.
Key data
- Atomic number
- 77
- Atomic mass
- 192.217 u
- Group / Period
- 9 / 6
- Block
- d-block
- Phase at STP
- Solid
- Density
- 22.56 g/cm³
- Melting point
- 2445.8 °C
- Boiling point
- 4129.9 °C
- Electron configuration
- [Xe] 4f14 5d7 6s2
Periodic table block
Iridium is in the d-block (group 9, period 6). Elements land in the d-block when their highest-energy electrons fill a d subshell — these are the transition metals in the middle of the table.
New to this? Periodic table blocks explained: s, p, d, and f
Common uses
- •Spark plugs
- •Crucibles
- •Asteroid impact marker
Discovery
Year: 1803
Discovered by: Smithson Tennant
Frequently asked questions
What is the atomic number of Iridium?
Iridium has atomic number 77. Its symbol is Ir and its atomic mass is 192.217 u.
What category of element is Iridium?
Iridium is classified as transition metals. It sits in group 9, period 6 of the periodic table.
What block of the periodic table is Iridium in?
Iridium is in the d-block (group 9, period 6). Its highest-energy electrons occupy the d subshell — you can see this in its electron configuration, [Xe] 4f14 5d7 6s2.
What is Iridium used for?
Common uses of Iridium include: Spark plugs, Crucibles, Asteroid impact marker.
When was Iridium discovered?
Iridium was discovered in 1803 by Smithson Tennant.
Play the game
Test your knowledge in The Lab
20-round element ID, cryptic 3-clue guesser, and an interactive periodic table.
Open The Lab →