Iridium is element number 77, a metal with the symbol Ir. Its name comes from Iris, the goddess of the rainbow in Greek myth.
Atomic number 77192.2
IrIridiumイリジウム (irijiumu)
Symbol
Ir
Atomic weight
192.2
Place in the table
Period 6 · Group 9
Atomic weight from the Chemical Society of Japan, “Table of Standard Atomic Weights with Four Significant Figures (2026)”.
Rainbow colors
Iridium’s compounds are as beautifully colored as a rainbow, which gave it its name. It was discovered in 1803.
Where it sits on the table
Iridium is in the sixth row of Group 9, with rhodium (rose) above and cobalt above that. Next door, in Group 10, is platinum.
Think about it
Q1How many colors do you count in a rainbow?
Q2Were there other elements whose compounds have beautiful colors?
Q3Look for elements named after goddesses in myths.
There is no single right answer. Talking it over with someone at home is a good way to learn.
Did you know? — The four elements found in 1803, rhodium (rose), palladium (the asteroid Pallas), osmium (smell) and iridium (rainbow), all have different name sources.