Ruthenium: the essentials
Ruthenium is a hard, white metal. It does not tarnish at room temperatures, but oxidises in air at about 800°C. The metal is not attacked by hot or cold acids or aqua regia, but when potassium chlorate is added to the solution, it oxidises explosively.
Ruthenium, rhodium, palladium, osmium, iridium, and platinum together make up a group of elements referred to as the platinum group metals (PGM).
Image adapted with permission from Prof James Marshall's (U. North Texas, USA) Walking Tour of the elements CD.
Ruthenium: historical information
Ruthenium was isolated in 1844 by Karl Karlovich Klaus, who obtained ruthenium from the part of crude platinum that is insoluble in aqua regia. It is possible that a Polish chemist Jedrzej Sniadecki had in fact isolated ruthenium from some platinum ores rather earlier than this in 1807 but his work was not ratified, apparently as he withdrew his claims. He called it vestium.
Ruthenium around us Read more »
Ruthenium has no biological role.
Ruthenium is found as the free metal, sometimes associated with platinum, osmium and iridium, in North and South America, and in South Africa. There are few ores. Ruthenium is also associated with nickel and deposits (from which it is recovered commercially).
|Location||ppb by weight||ppb by atoms||Links|
|Human||(no data) ppb by weight||(no data) atoms relative to C = 1000000|
Physical properties Read more »
Heat properties Read more »
- Melting point: 2607 [2334 °C (4233 °F)] K
- Boiling point: 4423 [4150 °C (7502 °F)] K
- Enthalpy of fusion: |203| kJ mol-1
Crystal structure Read more »
The solid state structure of ruthenium is: hcp (hexagonal close-packed).
Ruthenium: orbital properties Read more »
Ruthenium atoms have 44 electrons and the shell structure is 18.104.22.168.1. The ground state electronic configuration of neutral Ruthenium is [Kr].4d75s1 and the term symbol of Ruthenium is 5F5.
- Pauling electronegativity: 2.2 (Pauling units)
- First ionisation energy: 710.2 kJ mol‑1
- Second ionisation energy: 1620 kJ mol‑1
Isolation: it would not normally be necessary to make a sample of ruthenium in the laboratory as the metal is available, at a price, commercially. The industrial extraction of ruthenium is complex as the metal occurs in ores mixed with other metals such as rhodium, palladium, silver, platinum, and gold. Sometimes extraction of the precious metals such as iridium, rhodium, platinum and palladium is the main focus of a partiular industrial operation while in other cases it is a byproduct. The extraction is complex because of the other metals present and only worthwhile since ruthenium is useful as a specialist metal and is the basis of some catalysts in industry.
Preliminary treatment of the ore or base metal byproduct is required to remove silver, gold, palladium, and platinum. The residue is melted with sodium bisulphate (NaHSO4) and the resulting mixture extracted with water to give a solution containing rhodium sulphate, Rh2(SO4)3. The insoluble residue contains the ruthenium. The residue is melted with Na2O2 and extracted into water to extract the ruthenium and osmium salts (including [RuO4]2- and [OsO4(OH)2]2-). The residue contains iridium oxide, IrO2. Reaction of the salt with chlorine gas gives the volatile oxides RuO4 and OsO4. The ruthenium oxide is dissolved by treatment with hydrochloric acid to form H3RuCl6, and the ruthenium precipiated out as pure (NH4)3RuCl6 by treatment with NH4Cl. Evaporation to dryness and burning under hydrogen gas gives pure ruthenium.
Ruthenium isotopes Read more »
Ruthenium isotopes are used in several scientific and medical applications. Ru-99 is used for NMR studies. Ru-96 is used for the production of the radioisotopes Ru-94 and Ru-95. Ru-98 has been used to study excitations in atomic nuclei. Ru-100 has been used in isomeric cross section studies. Ru-101 has been used in studies related to the structure and vibrations of nuclei. Ru-102 has been used as a target for the production of the radioisotope Te-116. Ru-104 is used for the production of the radioisotope Rh-105 which has been suggested for the treatment of bone pain.
|96Ru||95.907599 (8)||5.54 (14)||0|
|98Ru||97.905287 (7)||1.87 (3)||0|
|99Ru||98.9059389 (23)||12.76 (14)||5/2||-0.6413|
|100Ru||99.9042192 (24)||12.60 (7)||0|
|101Ru||100.9055819 (24)||17.06 (2)||5/2||-0.7189|
|102Ru||101.9043485 (25)||31.55 (14)||0|
|104Ru||103.905424 (6)||18.62 (27)||0|