The ten densest chemical elements by measured room-temperature density, per the Royal Society of Chemistry periodic table: osmium (22.5872 g/cm³) edges iridium, with tantalum tenth.
Osmium (Os) is the densest chemical element at 22.5872 g/cm³, just ahead of iridium at 22.5622 g/cm³, according to the Royal Society of Chemistry periodic table. Platinum (21.5 g/cm³) is third and rhenium (20.8 g/cm³) fourth. The ranking uses the RSC's room-temperature density for each element, as checked in October 2026.
The densest elements are all heavy metals from the lower part of the periodic table: platinum-group metals such as osmium, iridium and platinum, a few refractory metals such as rhenium, tungsten and tantalum, and the actinides neptunium, plutonium and uranium. Every element in this top ten is more than 40% denser than lead. All figures come from one source, the Royal Society of Chemistry periodic table, so every value was measured and rounded the same way. Elements that have never been made in bulk, such as the superheavy elements beyond the actinides, have no measured density and are not ranked.
Osmium is the densest element, at 22.5872 g/cm³ in the RSC table. It is a hard, brittle, blue-grey platinum-group metal, used mainly in very hard alloys such as fountain-pen tips and electrical contacts.
At 22.5622 g/cm³, iridium is only 0.025 g/cm³ lighter than osmium per cubic centimetre. It is a hard, very corrosion-resistant platinum-group metal used in spark-plug tips and crucibles.
Platinum is third at 21.5 g/cm³. It is the best known of the platinum-group metals and is used in catalytic converters, jewellery and laboratory equipment.
Rhenium has a density of 20.8 g/cm³. It is one of the rarest elements in Earth's crust and is used in nickel-based superalloys for jet-engine turbine blades.
Neptunium, at 20.2 g/cm³, is the densest actinide on the list. It was the first transuranium element to be made and is produced in nuclear reactors.
Plutonium has a density of 19.7 g/cm³ in the RSC table. It has several solid forms with different densities, which makes its physical properties unusually complex.
Gold is listed at 19.3 g/cm³, the same figure the RSC gives for tungsten. Its density, resistance to tarnish and malleability have made it a store of value and a jewellery metal for thousands of years.
Tungsten is tied with gold at 19.3 g/cm³ in the RSC table. It also has the highest melting point of any metal, which is why it is used for lamp filaments and welding electrodes.
Uranium has a density of 19.1 g/cm³. It is the main fuel for nuclear power, and its high density is why depleted uranium is used in counterweights and armour-piercing rounds.
Tantalum completes the top ten at 16.4 g/cm³, well below the cluster of elements above 19 g/cm³. It is a corrosion-resistant refractory metal used in capacitors and surgical implants.
| # | Name | symbol | atomic_number | group | period |
|---|---|---|---|---|---|
| 1 | Osmium (Os) | Os | 76 | 8 | 6 |
| 2 | Iridium (Ir) | Ir | 77 | 9 | 6 |
| 3 | Platinum (Pt) | Pt | 78 | 10 | 6 |
| 4 | Rhenium (Re) | Re | 75 | 7 | 6 |
| 5 | Neptunium (Np) | Np | 93 | Actinide | 7 |
| 6 | Plutonium (Pu) | Pu | 94 | Actinide | 7 |
| 7 | Gold (Au) | Au | 79 | 11 | 6 |
| 8 | Tungsten (W) | W | 74 | 6 | 6 |
| 9 | Uranium (U) | U | 92 | Actinide | 7 |
| 10 | Tantalum (Ta) | Ta | 73 | 5 | 6 |
Elements are ranked by density in g/cm³ as listed in the fact box of each element's page in the Royal Society of Chemistry (RSC) periodic table, highest first. The RSC defines density as the mass of a substance that would fill 1 cm³ at room temperature. One source is used for every figure. The RSC gives osmium and iridium to four decimal places and the other elements to one, so values are shown exactly as the RSC prints them. Gold and tungsten are tied at 19.3 g/cm³ at that precision and are listed alphabetically. Only elements with a measured bulk density are eligible. Figures checked October 2026.
Osmium, but only just. The RSC lists osmium at 22.5872 g/cm³ and iridium at 22.5622 g/cm³, a gap of about 0.1%. The two are close because they are neighbours in the periodic table (atomic numbers 76 and 77) with similar atomic masses and atomic sizes.
In the RSC table they are tied: both are listed at 19.3 g/cm³. They are so close that tungsten has been used to fake gold bars by weight. This list puts gold first only because tied elements are listed alphabetically.
Lead is far less dense than the elements here. The RSC lists lead at 11.3 g/cm³, so even tantalum, in tenth place at 16.4 g/cm³, is more than 40% denser.
Reference tables round differently and sometimes use different measurement temperatures or crystal forms. This list uses only the RSC periodic table so that every element is measured the same way. Other tables give more decimal places for some elements, but the order of the top ten is the same.
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