Which Elements Are Liquid at Room Temperature?

Out of 118 known elements, only two are liquid at standard room conditions (25 °C and 1 atmosphere): mercury, a metal, and bromine, a nonmetal. A handful of others come surprisingly close.

Mercury: the liquid metal

Mercury melts at −38.8 °C and boils at 356.7 °C, so it’s liquid over a comfortable range around room temperature. It’s dense (13.53 g/cm³ — a steel bolt floats on it), silvery, and a reasonable conductor of electricity.

Why is it liquid when every other metal is solid? The explanation involves relativity. Mercury’s nucleus has 80 protons, and its innermost electrons move at a substantial fraction of the speed of light. That relativistic effect contracts mercury’s outer 6s orbital and pulls its two 6s electrons in close to the nucleus, where they’re held unusually tightly. They’re reluctant to join the shared “sea” of electrons that holds a metal together, so mercury’s metallic bonding is exceptionally weak. Computer simulations published in 2013 found that relativistic effects lower mercury’s melting point by about 105 degrees — without them, mercury would be a solid at room temperature.

Mercury was used for centuries in thermometers, barometers and some electrical switches. Because its vapour and many of its compounds are toxic, those uses have largely been phased out under the Minamata Convention.

Bromine: the liquid nonmetal

Bromine melts at −7.2 °C and boils at 58.8 °C. It’s a dense, dark red-brown liquid that gives off an orange, choking vapour even at room temperature. Its name comes from the Greek brōmos, meaning “stench”.

Bromine sits between the halogens that are gases (fluorine, chlorine) and the one that’s solid (iodine). As the halogen molecules get bigger down group 17, their London dispersion forces grow stronger, and bromine’s Br₂ molecules land exactly in the range that makes a liquid. See the halogens.

Liquid bromine is highly corrosive and causes severe burns; it’s handled in fume cupboards with heavy gloves.

The near-misses: metals that melt on a hot day

Element	Melting point
Francium	~27 °C (estimated)
Cesium	28.4 °C
Gallium	29.8 °C
Rubidium	39.3 °C

On a warm day, or in the palm of your hand, some of these would be liquid.

• Gallium is the famous one. It’s safe to handle and melts in your hand, leaving a silvery puddle. It also stays liquid up to about 2,200 °C, one of the widest liquid ranges of any element, which makes it useful for high-temperature thermometers. Like water, it expands when it freezes. Gallium is also a key ingredient in LEDs and in the semiconductor gallium arsenide.
• Cesium would melt in your hand too — but it would also react violently with the moisture on your skin, so it’s only ever handled in sealed containers.
• Francium would presumably be liquid at room temperature, but it’s so radioactive that a visible sample has never existed. Its melting point is an estimate.

Liquid alloys

Mixing metals can push the melting point below room temperature. Galinstan, an alloy of gallium, indium and tin, melts at about −19 °C and has replaced mercury in some thermometers because it’s far less toxic. Sodium–potassium alloy (NaK) is liquid at room temperature and has been used as a coolant in some nuclear reactors.

What about under different conditions?

“Room temperature” is a narrow window. At 30 °C, gallium and cesium join the liquids. At 40 °C, rubidium does too. The home page’s temperature slider lets you drag the temperature up and down and watch elements melt and boil — try it on the periodic table.

Quick answers

How many elements are liquid at room temperature? Two: mercury and bromine.

Is any gas liquid at room temperature? Not at normal pressure. Some gases, like chlorine, can be stored as liquids at room temperature under pressure.

Is water an element? No — water is a compound of hydrogen and oxygen, both of which are gases at room temperature. See which elements are gases at room temperature.