Periodic Table > Mercury
 

Terminology


Allotropes
Some elements exist in several different structural forms, these are called allotropes.


For more information on Murray Robertson’s image see Uses and properties facts below.

 

Fact box terminology


Group
Elements appear in columns or ‘groups’ in the periodic table. Members of a group typically have similar properties and electron configurations in their outer shell.


Period
Elements are laid out into rows or ‘periods’ so that similar chemical behaviour is observed in columns.


Block
Elements are organised into blocks by the orbital type in which the outer electrons are found. These blocks are named for the characteristic spectra they produce: sharp, principal, diffuse, and fundamental.


Atomic Number
The number of protons in the nucleus.


Atomic Radius/non -bonded (Å)
based on Van der Waals forces (where several isotopes exist, a value is presented for the most prevalent isotope). These values were calculated using a multitude of methods including crystallographic data, gas kinetic collision cross sections, critical densities, liquid state properties, for more details please refer to the CRC Handbook of Chemistry and Physics.


Electron Configuration
The arrangements of electrons above the last (closed shell) noble gas.


Isotopes
Elements are defined by the number of protons in its centre (nucleus), whilst the number of neutrons present can vary. The variations in the number of neutrons will create elements of different mass which are known as isotopes.


Melting Point (oC)
The temperature at which the solid-liquid phase change occurs.


Melting Point (K)
The temperature at which the solid-liquid phase change occurs.


Melting Point (oF)
The temperature at which the solid-liquid phase change occurs.


Boiling Point (oC)
The temperature at which the liquid-gas phase change occurs.


Boiling Point (K)
The temperature at which the liquid-gas phase change occurs.


Boiling Point (oF)
The temperature at which the liquid-gas phase change occurs.


Sublimation
Elements that do not possess a liquid phase at atmospheric pressure (1 atm) are described as going through a sublimation process.


Density (kgm-3)
Density is the weight of a substance that would fill 1 m3 (at 298 K unless otherwise stated).


Relative Atomic Mass
The mass of an atom relative to that of Carbon-12. This is approximately the sum of the number of protons and neutrons in the nucleus. Where more than one isotope exists the value given is the abundance weighted average.


Key Isotopes (% abundance)
An element must by definition have a fixed number of protons in its nucleus, and as such has a fixed atomic number, however variants of an element can exist with differing numbers of neutrons, and hence a different atomic masses (e.g. 12C has 6 protons and 6 neutrons and 13C has 6 protons and 7 neutrons).


CAS number
The Chemical Abstracts Service registry number is a unique identifier of a particular chemical, designed to prevent confusion arising from different languages and naming systems (where several isotopes exist, a value is presented for the most prevalent isotope).

Fact box

 
Group 12  Melting point -38.83 oC, -37.894 oF, 234.32 K 
Period Boiling point 356.62 oC, 673.916 oF, 629.77 K 
Block Density (kg m-3) 13546 
Atomic number 80  Relative atomic mass 200.59  
State at room temperature Liquid  Key isotopes 202Hg 
Electron configuration [Xe] 4f145d106s2  CAS number 7439-97-6 
ChemSpider ID 22373 ChemSpider is a free chemical structure database
 

Uses and properties terminology


Image Explanation

Murray Robertson is the artist behind the images which make up Visual Elements. This is where the artist explains his interpretation of the element and the science behind the picture.


Natural Abundance

Where this element is most commonly found in nature.


Biological Roles

The elements role within the body of humans, animals and plants. Also functionality in medical advancements both today and years ago.


Appearance

The description of the element in its natural form.

Uses and properties

 
Image explanation
This element is a complex metal that has much visual imagery associated with it, but the traditional alchemical symbol is the most iconic. The association with the planet Mercury (and hence astrology) is perhaps where many people will have seen this symbol used before. The dragon or serpent in the background is derived from early alchemical drawings and is often seen in association with the element.
Appearance
Mercury has fascinated people for millennia, as a heavy liquid metal that can be extracted easily by heating cinnabar, a red ore (mercury sulfide). Mercury is known to be dangerous in all its forms, and use is now confined to industry in the manufacture of chlorine and sodium hydroxide, although even here it is being phased out. Some is still used to treat seed corn to make it resistant to fungus disease, and in street lighting, dental amalgam and electrical apparatus. Older uses - in thermometers, in felt production and as a de-worming powder - have all been superseded. Mercury is widespread in the environment - every mouthful of food we eat contains a little. Our daily intake is about 0.01 milligramme (about a 0.3 grammes in a lifetime), and this we can cope with easily. However, one form of mercury - methylmercury - is particularly dangerous; it can be formed by micro-organisms in polluted waters, absorbed by fish and so eaten by people.
Uses
Mercury easily forms alloys, called amalgams, with other metals such as gold, silver and tin. Its ease in amalgamating with gold is made use of in recovering gold from its ores. It is used in the manufacture of sodium hydroxide and chlorine by electrolysis of brine. The metal is widely used in making advertising signs, mercury switches and other electrical apparatus. It is used in laboratory work for making thermometers, barometers, diffusion pumps and many other instruments. Other uses are in pesticides, dental work, batteries and catalysts. Because of its toxicity, all these uses are being phased out or are under review. Some mercury salts and organic mercury compounds are still important, including mercurous chloride (calomel), which is used in electrolysis, and mercuric sulfide (wermilion), a high-grade paint pigment.
Biological role
Mercury has no known biological role. It is a virulent poison, readily absorbed through the respiratory tract, the gastrointestinal tract or through the skin. It is a cumulative poison and dangerous levels are readily attained in air. It is now always handled with the utmost care.
Natural abundance
Mercury occurs very rarely free in nature, but can be found in ores, principally cinnabar. This is mostly found in Spain and Italy, which together produce about 50% of the world’s supply of this element. The metal is obtained by heating cinnabar in a current of air and condensing the vapour.
 
Atomic data terminology

Atomic radius/non -bonded (Å)
Based on Van der Waals forces (where several isotopes exist, a value is presented for the most prevalent isotope). These values were calculated using a multitude of methods including crystallographic data, gas kinetic collision cross sections, critical densities, liquid state properties,for more details please refer to the CRC Handbook of Chemistry and Physics.


Electron affinity (kJ mol-1)
The energy released when an additional electron is attached to the neutral atom and a negative ion is formed (where several isotopes exist, a value is presented for the most prevalent isotope). *


Electronegativity (Pauling scale)
The degree to which an atom attracts electrons towards itself, expressed on a relative scale as a function bond dissociation energies, Ed in eV. χA - χB =(eV)-1/2sqrt(Ed(AB)-[Ed(AA)+Ed(BB)]/2), with χH set as 2.2 (where several isotopes exist, a value is presented for the most prevalent isotope).


1st Ionisation energy (kJ mol-1)
The minimum energy required to remove an electron from a neutral atom in its ground state (where several isotopes exist, a value is presented for the most prevalent isotope).


Covalent radius (Å)
The size of the atom within a covalent bond, given for typical oxidation number and coordination (where several isotopes exist, a value is presented for the most prevalent isotope). ***

Atomic data

 
Atomic radius, non-bonded (Å) 2.230 Covalent radius (Å) 1.32
Electron affinity (kJ mol-1) Not stable Electronegativity
(Pauling scale)
1.900
Ionisation energies
(kJ mol-1)
 
1st
1007.065
2nd
1809.755
3rd
3299.796
4th
-
5th
-
6th
-
7th
-
8th
-
 

Mining/Sourcing Information

Data for this section of the data page has been provided by the British Geological Survey. To review the full report please click here or please look at their website here.


Key for numbers generated


Governance indicators

1 (low) = 0 to 2

2 (medium-low) = 3 to 4

3 (medium) = 5 to 6

4 (medium-high) = 7 to 8

5 (high) = 9


Reserve base distribution

1 (low) = 0 to 30 %

2 (medium-low) = 30 to 45 %

3 (medium) = 45 to 60 %

4 (medium-high) = 60 to 75 %

5 (high) = 75 %

(Where data are unavailable an arbitrary score of 2 was allocated. For example, Be, As, Na, S, In, Cl, Ca and Ge are allocated a score of 2 since reserve base information is unavailable. Reserve base data are also unavailable for coal; however, reserve data for 2008 are available from the Energy Information Administration (EIA).)


Production Concentration

1 (low) = 0 to 30 %

2 (medium-low) = 30 to 45 %

3 (medium) = 45 to 60 %

4 (medium-high) = 60 to 75 %

5 (high) = 75 %


Crustal Abundance

1 (low) = 100 to 1000 ppm

2 (medium-low) =10 to 100 ppm

3 (medium) = 1 to 10 ppm

4 (medium-high) = 0.1 to 1 ppm

5 (high) = 0.1 ppm

(Where data are unavailable an arbitrary score of 2 was allocated. For example, He is allocated a score of 2 since crustal abundance data is unavailable.)


Explanations for terminology


Crustal Abundance (ppm)

The abundance of an element in the Earth's crust in parts-per-million (ppm) i.e. The number of atoms of this element per 1 million atoms of crust.


Sourced

The country with the largest reserve base.


Reserve Base Distribution

This is a measure of the spread of future supplies, recording the percentage of a known resource likely to be available in the intermediate future (reserve base) located in the top three countries.


Production Concentrations

This reports the percentage of an element produced in the top three countries. The higher the value, the larger risk there is to supply.


Total Governance Factor

The World Bank produces a global percentile rank of political stability. The scoring system is given below, and the values for all three production countries were summed.


Relative Supply Risk Index

The Crustal Abundance, Reserve Base Distribution, Production Concentration and Governance Factor scores are summed and then divided by 2, to provide an overall Relative Supply Risk Index.

Supply risk

 
Scarcity factor 8.5
Country with largest reserve base Spain
Crustal abundance (ppm) 0.03
Leading producer China
Reserve base distribution (%) 37.50
Production concentration (%) 74.90
Total governance factor(production) 9
Top 3 countries (mined)
  • 1) Spain
  • 2) Italy
  • 3) Kyrgyzstan
Top 3 countries (production)
  • 1) China
  • 2) Kyrgyzstan
  • 3) Russia
 

Oxidation states and isotopes


Key for Isotopes


Half Life
  y years
  d days
  h hours
  m minutes
  s seconds
Mode of decay
  α alpha particle emission
  β negative beta (electron) emission
  β+ positron emission
  EC orbital electron capture
  sf spontaneous fission
  ββ double beta emission
  ECEC double orbital electron capture

Terminology


Common Oxidation states
The oxidation state of an atom is a measure of the degree of oxidation of an atom. It is defined as being the charge that an atom would have if all bonds were ionic. Free atoms have an oxidation state of 0, and the sum of oxidation numbers within a substance must equal the overall charge.


Important Oxidation states
The most common oxidation states of an element in its compounds.


Isotopes
Elements are defined by the number of protons in its centre (nucleus), whilst the number of neutrons present can vary. The variations in the number of neutrons will create elements of different mass which are known as isotopes.

Oxidation states and isotopes

 
Common oxidation states 2, 1
Isotopes Isotope Atomic mass Natural abundance (%) Half life Mode of decay
  196Hg 195.966 0.15 > 2.5 x 1018 α 
  198Hg 197.967 9.97
  199Hg 198.968 16.87
  200Hg 199.968 23.1
  201Hg 200.97 13.18
  202Hg 201.971 29.86
  204Hg 203.973 6.87
 

Pressure and temperature - advanced terminology


Molar Heat Capacity (J mol-1 K-1)

Molar heat capacity is the energy required to heat a mole of a substance by 1 K.


Young's modulus (GPa)

Young's modulus is a measure of the stiffness of a substance, that is, it provides a measure of how difficult it is to extend a material, with a value given by the ratio of tensile strength to tensile strain.


Shear modulus (GPa)

The shear modulus of a material is a measure of how difficult it is to deform a material, and is given by the ratio of the shear stress to the shear strain.


Bulk modulus (GPa)

The bulk modulus is a measure of how difficult to compress a substance. Given by the ratio of the pressure on a body to the fractional decrease in volume.


Vapour Pressure (Pa)

Vapour pressure is the measure of the propensity of a substance to evaporate. It is defined as the equilibrium pressure exerted by the gas produced above a substance in a closed system.

Pressure and temperature data – advanced

 
Molar heat capacity
(J mol-1 K-1)
27.983 Young's modulus (GPa) Unknown
Shear modulus (GPa) Unknown Bulk modulus (GPa) 25
Vapour pressure  
Temperature (K)
400 600 800 1000 1200 1400 1600 1800 2000 2200 2400
Pressure (Pa)
140 - - - - - - - - - -
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History

Cinnabar (aka vermilion, mercury sulfide, HgS), was used as a bright red pigment by the Palaeolithic painters of 30,000 years ago to decorate caves in Spain and France. Cinnabar would yield up its mercury simply on heating in a crucible, and the metal fascinated people because it was a liquid that would dissolve gold. The ancients used in on a large scale to extract alluvial gold from the sediment of rivers. The mercury dissolved the gold which could be reclaimed by distilling off the mercury.


The Almadén deposit in Spain provided Europe with its mercury. In the Americas, it was the Spanish conquerors who exploited the large deposits of cinnabar at Huancavelica in order to extract gold. In 1848 the miners of the Californian Gold Rush used mercury from the New Almaden Mines of California.


Although highly toxic, mercury had many uses, as in thermometers, but these are now strictly curtained.

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Podcasts

Listen to Mercury Podcast
Transcript :

Chemistry in Its Element - Mercury


(Promo)

 

You're listening to Chemistry in its element brought to you by Chemistry World, the magazine of the Royal Society of Chemistry.

 

(End promo)

 

Chris Smith

Hello! This week, we're exploring the link between Mad Hatters, mascara, the emperors of China and fishing floats; a strange combination you might say, but probably not as strange as this!

 

Fred Campbell

Could a man walk across a swimming pool filled with Mercury? Don't ask me how the conversation had reached this point, but being surrounded by friends, who would, it is fair to say, describe themselves as science illiterate, I knew it was up to me, the token scientist around the table, to give the definitive answer. "No." I confidently said, adding rather smugly, "it is nowhere near dense enough." The next morning I was rudely awakened by my ringing mobile; I was wrong! Elemental Mercury, a liquid at room temperature, is 13 times denser than water. Enough it turns out to support a man of average build and yes, if you type man sitting on Mercury into Google, you'll quickly find a 1972 photograph, published in National Geographic of a man suited and booted, sat unaided, albeit a little nervously, on top of a tank of rippling Mercury. I've been unequivocally proved wrong, but within a fraction of a second, this feeling had been transformed to sheer amazement. Amazement not just at the fact that Mercury was so dense it could support a man, but more pressingly that the man in question was very likely giving himself a lethal dose of Mercury poisoning in one fatal pose. Surely even in 1972, this kind of activity was seen as an exceptionally bad idea. This of course was not the first time that man has been lowered in by Mercury. 

 

With its Greek name, hydrargyrum, literally meaning liquid silver it's perhaps unsurprising that for the last three millennia, civilizations have been transfixed, believing Mercury held wondrous physical and spiritual properties, but often those who dabbled reached an unpleasant and mercurial end. The Romans were renowned for using it in cosmetics, often disfiguring their faces in the process. The Egyptians were buried with it to illustrate their civilizations' mining prowess and the ancient Chinese drank lethal Mercury cocktails seeking eternal life and well-being. In deed, Chinese first emperor, Qin Shi Huang is said to have believed so strongly in the magical properties of Mercury that he died seeking immortality by coughing out  Mercury and powdered jade, pick-me-up. His tomb yet to be fully unearthed is thought to be surrounded by great rivers of the element and guarded by the 8000 soldiers of the terracotta army. 

 

Skipping forward to the 18th Century and for the first time, psychological illnesses were attributed to Mercury exposure. The madness of many millionaires was blamed on the extensive use of mercuric nitrate in the hat industry and the phrase Mad as a Hatter  was coined. The link almost certainly inspired Lewis Carroll to dream up the Mad Hatter, although much debate hangs over whether he is in fact displaying the symptoms of Mercury poisoning. From this point on, the hazards of Mercury were well documented; but despite its toxicity, it continued to find many uses in everyday applications throughout the last century. To forego reeling off a huge list of weird and wonderful uses for Mercury, I would just briefly mention my personal favourite, fishing floats, used to maintain in an regular wobble on the water surface, the Mercury float proves so alluring to fish that even now after its use has been globally banned, there is active research to find a replacement to do an equal job. It can still be found swirling around in dentistry, where it is used in amalgam fillings and it remains an important ingredient of many mascaras.   But both these sources of Mercury are currently under threat. Even the humble thermometer is gradually being phased out to be replaced by alcohol filled digital or thermistor-based instruments. 

 

On one hand, it saddens me to think that Mercury will eventually be an elemental artefact sitting hopelessly between Gold and Thallium in the periodic table, but on the other, it constantly reminds me of the dangers that hide behind the façade of its beautiful silver lustre. As for the man sitting on the vat of Mercury, unfortunately I'm still waiting to hear back from National Geographic, for his sake though, we can only hope that he is living a long and healthy life and has not joined the long list of Mercury's many victims.

 

Chris Smith

Chemistry World's Fred Campbell on the uses and abuses of element number 80, Quick Silver, otherwise known as Mercury. Here's a taste of what to look forward to next time.

 

Adina Payton

The first thing most people think about when this element is mentioned is barium enema or barium swallow, sickly memories often surface off the radiology clinic, where the nice nurse asked you, 'what flavour would you like, strawberry or banana'.

 

Chris Smith

A hard act to swallow, you could say, but thankfully a very digestible account of barium. That's coming up with Adina Payton on next week's Chemistry in its elements. I'm Chris Smith, thank you for listening and goodbye!

 

(Promo)

 

Chemistry in its elementis brought to you by the Royal Society of Chemistry and produced by thenakedscientists dot com. There's more information and other episodes of Chemistry in its Elements on our web site at chemistryworld dot org forward slash elements.

 

(End Promo)

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  Help Text

Resources

Description :
Mercury poisoning and the origins of the phrase 'mad as a hatter'.
Description :
Assessment for Learning is an effective way of actively involving students in their learning. This is a series of plans based around chemistry topics.
Description :
When concentrated hydrochloric acid is added to a very dilute solution of copper sulfate, the pale blue solution slowly turns yellow-green on the formation of a copper chloride complex. When concentr...
Description :
The purpose of this experiment is to observe and interpret some of the chemistry of three first row transition elements and to compare them with a typical s-block element.
Description :
The Periodic Table allows chemists to see similarities and trends in the properties of chemical elements. This experiment illustrates some properties of the common transition elements and their compo...
Description :
In this experiment you will be looking at a group of transition elements chromium, molybdenum and tungsten.
 

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References

 
Images:  Visual Elements © Murray Robertson 2011
Mining and Sourcing data:  British Geological Survey – natural environment research council.
Text:  John Emsley Nature’s Building Blocks: An A-Z Guide to the Elements, Oxford University Press, 2nd Edition, 2011.
Additional information for platinum, gold, neodymium and dysprosium obtained from Material Value Consultancy Ltd www.matvalue.com
Data: CRC Handbook of Chemistry and Physics, CRC Press, 92nd Edition, 2011.
G. W. C. Kaye and T. H. Laby Tables of Physical and Chemical Constants, Longman, 16th Edition, 1995.
Members of the RSC can access these books through our library.