Ruthenium (Ru)
Element 44 · Transition metal · Solid at 25 °C · Group 8, Period 5
Ruthenium, a hard platinum-group metal, hardens platinum alloys and coats electrical contacts and hard-disk components.
On the periodic table, ruthenium sits in group 8 in period 5. It is one of 38 elements classified as a transition metal, and at room temperature (25 °C) it is a solid.
Transition metals occupy the wide d-block in the middle of the table. As a family they are hard, dense, high-melting metals that conduct heat and electricity well. Their partly filled d-orbitals let many of them take several oxidation states, form vividly colored compounds, and act as catalysts — which is why so much of industry, and so much of biology, runs on this block.
Properties of ruthenium
| Atomic number (Z) | 44 |
|---|---|
| Symbol | Ru |
| Atomic mass | 101.07 |
| Category | Transition metal |
| Group | 8 |
| Period | 5 |
| Block | d-block |
| Metal / nonmetal | Metal |
| State at 25 °C | Solid |
| Electron configuration | [Kr] 4d7 5s1 |
| Electronegativity (Pauling) | 2.2 |
| Melting point | 2,334 °C (2,607.15 K / 4,233.2 °F) |
| Boiling point | 4,150 °C (4,423.15 K / 7,502 °F) |
| Density | 12.45 g/cm³ |
Position in the periodic table
Ruthenium shares group 8 with Iron (Fe), Osmium (Os), Hassium (Hs). Elements in the same group have the same number of outer electrons, so they tend to behave alike chemically — comparing them is one of the fastest ways to see periodic trends in action.
Within this dataset, its melting point is the #9 highest of the 102 elements with measured melting points.
Physical properties
Ruthenium melts at 2,334 °C (2,607.15 K / 4,233.2 °F) and boils at 4,150 °C (4,423.15 K / 7,502 °F), giving it a liquid range of about 1,816 °C at standard pressure.
Its density is 12.45 g/cm³.
See also: the interactive periodic table, how to read the periodic table, periodic trends.