Is Mercury Solid, Liquid or Gas? (+ 3 Things to Know)

Mercury is a liquid at standard temperature and pressure (STP). ¹ Its melting point is -38.83 °C (-37.89 °F) and its boiling point is 356.73 °C (674.11 °F), which means it exists as a liquid at room temperature. ²

Well, this was just a simple answer. But there are few more things to know about this topic which will make your concept super clear.

So let’s dive right into it.

Why does mercury exist as a liquid at room temperature?

Mercury is a unique element in that it exists as a liquid at room temperature because of its low melting point and boiling point. Mercury has a melting point of -38.83°C and a boiling point of 356.73°C, which means that it remains in a liquid state at temperatures between these two points.

The reason for its low melting and boiling points is due to the fact that mercury has a weak metallic bond between its atoms.

Metallic bonding is a type of chemical bonding that occurs between metal atoms where valence electrons are free to move throughout the metal lattice, creating a sea of electrons. The strength of the metallic bond depends on the number of valence electrons and the distance between atoms. ³

In the case of mercury, it has a weak metallic bond due to its low number of valence electrons (two) and its large atomic radius. ⁴

As a result, the metallic bond between mercury atoms is not strong enough to hold the atoms together in a solid lattice structure at room temperature, and mercury remains in a liquid state.

Furthermore, mercury is also a dense element with a high atomic weight, which means that the forces of attraction between its atoms are relatively strong. These attractive forces further contribute to the liquid state of mercury at room temperature.

Does mercury exist in a solid state?

Yes, mercury can exist in a solid state at low temperatures. The melting point of mercury is -38.83°C, which means that if its temperature is lowered below this point, it will solidify and form a solid phase. The solid form of mercury is called “quicksilver” or “mercury amalgam.” ^{5 6}

However, the solid state of mercury is not stable at room temperature and atmospheric pressure.

In fact, it has a very low freezing point, and even small changes in temperature or pressure can cause it to melt and return to its liquid state. Therefore, it is challenging to maintain solid mercury under normal conditions.

It is worth noting that solid mercury has some unique properties, such as its low coefficient of thermal expansion, which means that it does not expand or contract much when its temperature changes.

This property makes mercury useful in thermometers and other precision instruments. ⁷ However, due to its toxic nature, the use of mercury is becoming increasingly restricted, and safer alternatives are being developed. ⁸

How is liquid mercury different from solid mercury?

Liquid mercury and solid mercury (also known as “quicksilver”) are different states of the same element, and they have some distinct properties.

1) Physical appearance

One significant difference between liquid and solid mercury is their physical appearance. Liquid mercury is a silvery-white metal that is shiny and reflective, while solid mercury is a soft, dull gray-white material. In its solid state, mercury forms small, rounded beads or globules, while in its liquid state, it forms a shiny, flowing liquid.

2) Density

Another difference between liquid and solid mercury is their density. Liquid mercury has a density of 13.5 g/cm³, while solid mercury has a density of about 14.184 g/cm³. ^{9 10}

3) Coefficient of thermal expansion

Additionally, liquid mercury has a much higher coefficient of thermal expansion compared to solid mercury. This means that its volume increases significantly when heated, which makes it useful in thermometers. On the other hand, solid mercury has a very low coefficient of thermal expansion, which means that it does not expand or contract much when its temperature changes, making it useful in precision instruments.

Finally, it is worth noting that both liquid and solid mercury are highly toxic and pose a significant risk to human health and the environment. Therefore, it is essential to handle them with extreme care and dispose of them properly. ¹¹

Further reading

Is Phosphorus a Solid, Liquid or Gas?
Is Sodium a Solid, Liquid or Gas?
Is Oxygen Solid, Liquid or Gas?
Is Lithium Solid, Liquid or Gas?
Is Magnesium a Solid, Liquid or Gas?

1. Mit Engineering. (2012, November 6). Mit Engineering. https://engineering.mit.edu/engage/ask-an-engineer/why-is-mercury-liquid-at-room-temperature/
2. Climate Change Canada, E. A. (n.d.). Mercury: chemical properties – Canada.ca. Mercury: Chemical Properties – Canada.ca. https://www.canada.ca/en/environment-climate-change/services/pollutants/mercury-environment/about/chemical-properties.html
3. metallic bonding. (n.d.). Metallic Bonding. https://www.chemguide.co.uk/atoms/bonding/metallic.html
4. Gross, M. (2011). Mercury. Encyclopedia of Child Behavior and Development, 943–945. https://doi.org/10.1007/978-0-387-79061-9_1767
5. Group on the Evaluation of Carcinogenic Risks to Humans, I. W. (1993, January 1). Mercury and Mercury Compounds – Beryllium, Cadmium, Mercury, and Exposures in the Glass Manufacturing Industry – NCBI Bookshelf. Mercury and Mercury Compounds – Beryllium, Cadmium, Mercury, and Exposures in the Glass Manufacturing Industry – NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK499780/
6. Basic Information about Mercury | US EPA. (2015, August 20). US EPA. https://www.epa.gov/mercury/basic-information-about-mercury
7. AMNH https://www.amnh.org/explore/ology/ology-cards/355-mercury
8. Health Effects of Exposures to Mercury | US EPA. (2015, September 3). US EPA. https://www.epa.gov/mercury/health-effects-exposures-mercury
9. It’s Elemental – The Element Mercury. (n.d.). It’s Elemental – the Element Mercury. https://education.jlab.org/itselemental/ele080.html
10. Mercury (element) – Wikipedia. (2015, February 18). Mercury (Element) – Wikipedia. https://en.wikipedia.org/wiki/Mercury_(element)
11. Mercury exposure and poisoning. (n.d.). Mercury Exposure and Poisoning – Better Health Channel. http://www.betterhealth.vic.gov.au/health/healthyliving/mercury-exposure-and-poisoning