Rhodium (Rh) VS Iridium (Ir)
A definitive side-by-side comparison of two essential element profiles.
VS
Main Differences
Rhodium (Rh) is an element in the transition metals category with an atomic number of 45. Iridium (Ir) is an element in the transition metals category with an atomic number of 77.
Iridium (Ir) is 1.8x denser than Rhodium (Rh). However, Iridium (Ir) melts at a higher temperature than Rhodium (Rh) (a difference of 482.0 Kelvin).
Where do the names come from?
Rh Rhodium (Rh) Naming History
The name Rhodium is derived from the Greek ''rhodon'', meaning rose coloured.
Ir Iridium (Ir) Naming History
The name Iridium is derived from the Greek goddess of the rainbow, Iris.
Related Comparisons
Compare
Rhodium (Rh)
Iridium (Ir)
Category
Transition Metals
Transition Metals
Atomic Number
45
77
Symbol
Rh
Ir
Atomic Mass
102.906 u
192.217 u
Group
9
9
Period
5
6
Block
d-block
d-block
Standard State (at 20°C)
solid
solid
Density
12.41 g/cm³
22.56 g/cm³
Melting Point (°C)
1963°C
2446°C
Melting Point (°F)
3565°F
4435°F
Melting Point (K)
2237 K
2719 K
Boiling Point (°C)
3695°C
4428°C
Boiling Point (°F)
6683°F
8002°F
Boiling Point (K)
3968 K
4701 K
Year Discovered:
1803
1803
CAS Number
7440-16-6
7439-88-5
Origin of Name:
The name is derived from the Greek ''rhodon'', meaning rose coloured.
The name is derived from the Greek goddess of the rainbow, Iris.