Platinum (Pt)
Element 78 · Transition metal · Solid at 25 °C · Group 10, Period 6
Platinum is prized for jewelry and indispensable as a catalyst; for over a century a platinum-iridium cylinder literally defined the kilogram.
On the periodic table, platinum sits in group 10 in period 6. 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 platinum
| Atomic number (Z) | 78 |
|---|---|
| Symbol | Pt |
| Atomic mass | 195.08 |
| Category | Transition metal |
| Group | 10 |
| Period | 6 |
| Block | d-block |
| Metal / nonmetal | Metal |
| State at 25 °C | Solid |
| Electron configuration | [Xe] 4f14 5d9 6s1 |
| Electronegativity (Pauling) | 2.28 |
| Melting point | 1,768.3 °C (2,041.45 K / 3,214.94 °F) |
| Boiling point | 3,825 °C (4,098.15 K / 6,917 °F) |
| Density | 21.45 g/cm³ |
Position in the periodic table
Platinum shares group 10 with Nickel (Ni), Palladium (Pd), Darmstadtium (Ds). 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, it has the #3 highest measured density of the 97 elements with recorded values.
Physical properties
Platinum melts at 1,768.3 °C (2,041.45 K / 3,214.94 °F) and boils at 3,825 °C (4,098.15 K / 6,917 °F), giving it a liquid range of about 2,056.7 °C at standard pressure.
Its density is 21.45 g/cm³.
See also: the interactive periodic table, how to read the periodic table, periodic trends.