Density of the elements

Density is mass per unit volume, here in grams per cubic centimetre, the same number as kilograms per litre. Solids and liquids are near room temperature, and the gases are measured as gas at 0 °C and 1 atm. The values are PubChem’s, published by the US National Institutes of Health. It gives one for 96 of the 118 elements; the rest are hatched in the table below rather than coloured as if they were zero.

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H 0.00009, hydrogen He 0.00018, helium Li 0.534, lithium Be 1.85, beryllium B 2.37, boron C 2.27, carbon N 0.0013, nitrogen O 0.0014, oxygen F 0.0017, fluorine Ne 0.00090, neon Na 0.97, sodium Mg 1.74, magnesium Al 2.7, aluminium Si 2.33, silicon P 1.82, phosphorus S 2.07, sulfur Cl 0.0032, chlorine Ar 0.0018, argon K 0.89, potassium Ca 1.54, calcium Sc 2.99, scandium Ti 4.5, titanium V 6, vanadium Cr 7.15, chromium Mn 7.3, manganese Fe 7.87, iron Co 8.86, cobalt Ni 8.91, nickel Cu 8.93, copper Zn 7.13, zinc Ga 5.91, gallium Ge 5.32, germanium As 5.78, arsenic Se 4.81, selenium Br 3.11, bromine Kr 0.0037, krypton Rb 1.53, rubidium Sr 2.64, strontium Y 4.47, yttrium Zr 6.52, zirconium Nb 8.57, niobium Mo 10.2, molybdenum Tc 11, technetium Ru 12.1, ruthenium Rh 12.4, rhodium Pd 12, palladium Ag 10.5, silver Cd 8.69, cadmium In 7.31, indium Sn 7.29, tin Sb 6.69, antimony Te 6.23, tellurium I 4.93, iodine Xe 0.0059, xenon Cs 1.93, caesium Ba 3.62, barium La 6.15, lanthanum Ce 6.77, cerium Pr 6.77, praseodymium Nd 7.01, neodymium Pm 7.26, promethium Sm 7.52, samarium Eu 5.24, europium Gd 7.9, gadolinium Tb 8.23, terbium Dy 8.55, dysprosium Ho 8.8, holmium Er 9.07, erbium Tm 9.32, thulium Yb 6.9, ytterbium Lu 9.84, lutetium Hf 13.3, hafnium Ta 16.4, tantalum W 19.3, tungsten Re 20.8, rhenium Os 22.6, osmium Ir 22.4, iridium Pt 21.5, platinum Au 19.3, gold Hg 13.5, mercury Tl 11.8, thallium Pb 11.3, lead Bi 9.81, bismuth Po 9.32, polonium At 7, astatine Rn 0.0097, radon Fr no value, francium Ra 5, radium Ac 10.1, actinium Th 11.7, thorium Pa 15.4, protactinium U 19, uranium Np 20.3, neptunium Pu 19.8, plutonium Am 13.7, americium Cm 13.5, curium Bk 14, berkelium Cf no value, californium Es no value, einsteinium Fm no value, fermium Md no value, mendelevium No no value, nobelium Lr no value, lawrencium Rf no value, rutherfordium Db no value, dubnium Sg no value, seaborgium Bh no value, bohrium Hs no value, hassium Mt no value, meitnerium Ds no value, darmstadtium Rg no value, roentgenium Cn no value, copernicium Nh no value, nihonium Fl no value, flerovium Mc no value, moscovium Lv no value, livermorium Ts no value, tennessine Og no value, oganesson

How it changes across a period and down a group

Density comes from two trends pulling in opposite directions: atomic mass rises steadily with atomic number, while atomic volume shrinks across a period and grows down a group. The heaviest atoms packed most tightly win, which puts the peak in the middle and late transition metals.

The densest element in each row shows it: copper, rhodium and osmium for periods 4, 5 and 6, at 8.933, 12.4 and 22.57 g/cm³. Osmium, at 22.57 g/cm³, is the densest in PubChem’s table, just ahead of iridium at 22.42.

Down a group density generally rises, because the mass each period adds grows faster than the volume. The exceptions are all near the top of the table, where beryllium, sodium and magnesium are each denser than the element below them.

Extremes and exceptions

Densest and least dense

• Osmium, 22.57 g/cm³
• Iridium, 22.42 g/cm³
• Platinum, 21.46 g/cm³
• Hydrogen, 0.00008988 g/cm³
• Helium, 0.0001785 g/cm³
• Neon, 0.0008999 g/cm³

The three densest and the three least dense elements PubChem lists. The least dense are all gases.

The densest element in each period

• Period 4: copper, 8.933 g/cm³
• Period 5: rhodium, 12.4 g/cm³
• Period 6: osmium, 22.57 g/cm³
• Period 7: neptunium, 20.25 g/cm³

From period 4 on, each row’s densest element is a transition metal or, in period 7, an actinide.

Less dense than the element below it

• Beryllium to magnesium: 1.85 to 1.74 g/cm³
• Sodium to potassium: 0.97 to 0.89 g/cm³
• Magnesium to calcium: 1.74 to 1.54 g/cm³

In the main groups, where the volume a period adds outpaces the mass. Each is an s-block metal near the top of the table.

The 96 elements with a value, ranked

Equal values share a rank, marked with =.

No value in PubChem’s table, so not ranked: francium, californium, einsteinium, fermium, mendelevium, nobelium, lawrencium, rutherfordium, dubnium, seaborgium, bohrium, hassium, meitnerium, darmstadtium, roentgenium, copernicium, nihonium, flerovium, moscovium, livermorium, tennessine and oganesson.

The values are facts and free to use; this table’s selection and presentation are © 2026 ScienceQuest.

Caveats

• The gases are measured as gases, which is why they sit so far below everything else: radon, the densest gas here at 0.00973 g/cm³, is still 55 times less dense than lithium, the least dense solid.
• Where an element has more than one solid form the figure is for one of them: carbon’s 2.267 g/cm³ is graphite, not diamond.
• Densities change with temperature, falling slightly as a solid or liquid warms and expands, and a great deal for a gas, so compare values measured under the same conditions.
• Francium has no value in PubChem’s table, and nor does any element from californium on.
• Astatine’s 7 g/cm³ is a prediction, not a measurement, which is why the list flags it. No piece of astatine large enough to see has ever existed, because the heat of its own decay would vaporise it.

See also

• The interactive periodic table, with every element’s details
• Density calculator, for mass, volume and density of a sample
• All the elements, each with its own page of data