Rh redirects here. For other uses, see rh (disambiguation)

45 ruthenium ← rhodium → palladium Co ↑ Rh ↓ Ir Periodic Table - Extended Periodic Table
General
Name, Symbol, Number	rhodium, Rh, 45
Chemical series	transition metals
Group, Period, Block	9, 5, d
Appearance	silvery white metallic
Standard atomic weight	102.90550(2)  g·mol−1
Electron configuration	[Kr] 4d8 5s1
Electrons per shell	2, 8, 18, 16, 1
Physical properties
Phase	solid
Density (near r.t.)	12.41  g·cm−3
Liquid density at m.p.	10.7  g·cm−3
Melting point	2237 K (1964 °C, 3567 °F)
Boiling point	3968 K (3695 °C, 6683 °F)
Heat of fusion	26.59  kJ·mol−1
Heat of vaporization	494  kJ·mol−1
Heat capacity	(25 °C) 24.98  J·mol−1·K−1
Vapor pressure P(Pa) 1 10 100 1 k 10 k 100 k at T(K) 2288 2496 2749 3063 3405 3997
Atomic properties
Crystal structure	cubic face centered
Oxidation states	4, 3, 2, 1[1] (amphoteric oxide)
Electronegativity	2.28 (Pauling scale)
Ionization energies	1st: 719.7 kJ/mol
	2nd: 1740 kJ/mol
	3rd: 2997 kJ/mol
Atomic radius	135  pm
Atomic radius (calc.)	173  pm
Covalent radius	135  pm
Miscellaneous
Magnetic ordering	no data
Electrical resistivity	(0 °C) 43.3 nΩ·m
Thermal conductivity	(300 K) 150  W·m−1·K−1
Thermal expansion	(25 °C) 8.2  µm·m−1·K−1
Speed of sound (thin rod)	(20 °C) 4700 m/s
Young's modulus	380  GPa
Shear modulus	150  GPa
Bulk modulus	275  GPa
Poisson ratio	0.26
Mohs hardness	6.0
Vickers hardness	1246  MPa
Brinell hardness	1100  MPa
CAS registry number	7440-16-6
Selected isotopes
Main article: Isotopes of rhodium iso NA half-life DM DE (MeV) DP 99Rh syn 16.1 d ε - 99Ru γ 0.089, 0.353, 0.528 - 101mRh syn 4.34 d ε - 101Ru IT 0.157 101Rh γ 0.306, 0.545 - 101Rh syn 3.3 y ε - 101Ru γ 0.127, 0.198, 0.325 - 102mRh syn 2.9 y ε - 102Ru γ 0.475, 0.631, 0.697, 1.046 - 102Rh syn 207 d ε - 102Ru β+ 0.826, 1.301 102Ru β- 1.151 102Pd γ 0.475, 0.628 - 103Rh 100% 103Rh is stable with 58 neutrons 105Rh syn 35.36 h β- 0.247, 0.260, 0.566 105Pd γ 0.306, 0.318 -
References

Rhodium (pronounced /ˈroʊdiəm/) is a chemical element with the symbol Rh and atomic number 45. A rare silvery-white hard transition metal and a member of the platinum group, rhodium is found in platinum ores and is used in alloys with platinum and as a catalyst. It is usually the most expensive precious metal^[2], though it is sometimes surpassed by rhenium, depending on the market.