Atomic number:45

Group numbers:9

Period:5

Electronic configuration:[Kr] 4d⁸ 5s¹

Formal oxidation number:+3

Electronegativities:2.28

Atomic radius / pm:134.5

Relative atomic mass:102.90550 ± 0.00002

 

Rhodium was discovered by William Hyde Wollaston (GB) in 1804. The origin of the name comes from the Greek word rhodon meaning rose. It is a hard, silvery-white metal, inert in air and acids that reacts with fused alkalis. Rhodium is obtained as a by-product of nickel production. It is used as a coating to prevent wear on high quality science equipment and with platinum to make thermocouples.

Density / g dm^-3:12410 (293 K)

 10650 (m.p.)

Molar volume / cm³mol^-1:8.29 (293 K)

 9.66 (m.p.)

Electrical resistivity / μΩcm:4.51 (20 °C)

Thermal conductivity / W m^-1K^-1:150

Melting point / °C:1964

Boiling point / °C:3695

Heat of fusion / kJ mol^-1:21.55

Heat of vaporization / kJ mol^-1:494.34

Heat of atomization / kJ mol^-1:555.59

1st ionization energy / kJ mol^-1:719.68

2nd ionization energy / kJ mol^-1:1744.47

3rd ionization energy / kJ mol^-1:2996.86

in the atmosphere / ppm:-

in the Earth's crust / ppm:0.005

in the oceans / ppm:1E-10