Periodic Table

Mercury

Transition Metal

Quick Facts about Mercury

Au
  • liquid- state of matter at room temperature
  • Stable- has at least one stable isotope
  • +2, +1- common oxidation states in compounds
  • RHL- crystal structure, atomic arrangement in solid form
Tl

Mercury (Hg) is element 80 on the periodic table. Atomic mass of Hg: 200.5900 u. Hg is in period 6, group 12. Melting point of Hg: 234.32 K.Density of Hg: 13.53 g/cm³.

Why Mercury Matters

The only metal that's liquid at room temperature—beautiful but deadly

In Your Home

  • Old thermometers (being phased out)
  • Some fluorescent light bulbs
  • Old dental fillings (amalgam)
  • Antique mirrors and barometers

Industry Uses

LightingFluorescent and HID lamps (small amounts)
DentalAmalgam fillings (declining use)
MiningGold extraction (illegal in many places)
ChemicalChlor-alkali process (being replaced)

In Your Body

✗ Not essential

No biological role. Highly toxic to nervous system. Bioaccumulates in fish as methylmercury. Crosses blood-brain barrier.

Safety: Extremely toxic. Causes neurological damage, kidney damage, birth defects. 'Mad as a hatter' came from mercury poisoning in hat-making.

Discovery of Mercury

Discovered by Known to the ancients.,

Name origin: From the Roman god Mercury; symbol from Latin: hydrargyrus (liquid silver).

History & Events

1500 BCE
Ancient Use
Egyptians and Chinese used cinnabar (mercury sulfide) as pigment and medicine
1643
Barometer
Evangelista Torricelli invented mercury barometer, proving air pressure
1956
Minamata Disease
Mercury poisoning from industrial waste killed and disabled thousands in Japan

Why "Hg" for Mercury?

HgHydrargyrum(Latin)

The symbol Hg comes from "Hydrargyrum," Latin for "liquid silver" (from Greek "hydor" = water + "argyros" = silver). The English name "Mercury" refers to the Roman god known for speed, reflecting the liquid metal's mobility.

About Mercury

Heavy silvery liquid metallic element, belongs to the zinc group. Used in thermometers, barometers and other scientific apparatus. Less reactive than zinc and cadmium, does not displace hydrogen from acids. Forms a number of complexes and organomercury compounds.

Atomic Properties of Hg

Atomic Number of Hg
80
Atomic Mass of Hg
200.5900 u
Electron Configuration
[Xe] 4f14 5d10 6s2
Electronegativity
2.00
Block
d-block
Group
12
Period
6

Physical Properties of Hg

Phase (STP)
liquid
Melting Point of Hg
234.32 K
Boiling Point of Hg
629.88 K
Density of Hg
13.5340 g/cm3

Thermal Properties

Heat of Fusion
2.29 kJ/mol
Heat of Vaporization
58.50 kJ/mol
Specific Heat
0.14 J/g·K
Molar Heat Capacity
27.98 J/mol·K
Thermal Conductivity
8.30 W/m·K

Atomic Radii

Calculated
150 pm
Covalent
133 pm
Van der Waals
223 pm
Metallic
139 pm

Common Misconceptions

Wrong:A little mercury exposure is okay.
Correct:There is no safe level of mercury. Even small exposures accumulate and cause harm over time.
Wrong:Mercury in vaccines is dangerous.
Correct:Thimerosal (ethylmercury) is rapidly eliminated from body, unlike methylmercury in fish. It's been removed from most vaccines anyway.
Wrong:Breaking a thermometer requires hazmat cleanup.
Correct:Small spills can be cleaned safely with proper precautions, but never vacuum mercury!

Isotopes of Mercury

Mercury has 7 naturally occurring isotopes.

IsotopeAtomic Mass (u)AbundanceHalf-LifeDecay Mode
19680Hg (Hg-196)Mercury-196 isotope195.96583260.1500%
19880Hg (Hg-198)Mercury-198 isotope197.96676869.970%
19980Hg (Hg-199)Mercury-199 isotope198.968280616.87%
20080Hg (Hg-200)Mercury-200 isotope199.968326623.10%
20180Hg (Hg-201)Mercury-201 isotope200.970302813.18%
20280Hg (Hg-202)Mercury-202 isotope201.970643429.86%
20480Hg (Hg-204)Mercury-204 isotope203.9734946.870%

Data source: NIH PubChem (aggregated from IUPAC, NIST)

Isotope Applications

Isotopes of Mercury have important real-world applications in science and industry.

Geochronology & Dating

Mercury isotope ratios are used as environmental tracers to identify sources of mercury pollution and track atmospheric mercury deposition. Mass-independent fractionation of mercury isotopes provides unique signatures for different mercury sources.

Medical Applications

197Hg was historically used in brain and kidney scanning before being replaced by safer radiopharmaceuticals. 203Hg has been used in research for studying mercury distribution in biological systems.

Abundance

Earth's Crust
85.00 μg/kg
Seawater
3.00×10-5 mg/L

Uses

Used in thermometers, barometers, and batteries. Also used in electrical switches and mercury-vapor lighting products.

Sources

Virtually all mercury comes from cinnabar or mercury sulfide (HgS). Some sources of red cinnabar are so rich in mercury that droplets of elemental mercury can be found in random samples.

Geochemistry

Goldschmidt
chalcophile

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