ChemTalk

The Mobile Element Mercury

Mercury element

The Element Mercury

Mercury element is a silvery-white transition metal on the periodic table that is liquid at standard temperature. It is known for its mobility and high surface tension; both of which cause it to go rolling on surfaces and into the formation of spheres. Moreover, it has a high density which allows most other metals to float on top. It was once used in batteries, fluorescent lights, thermometers, and more. However, over time the toxic metal has been replaced with safer alternatives. Find out more facts & properties about this unique metal down below!

Cool Facts About Mercury

  1. Its chemical symbol is Hg, which stood for its original name hydrargyrum. In greek, this name translates to “living water” which references mercury’s lively movement on flat surfaces. For this reason, it is also known as “quicksilver”. Moreover, its current name comes from the roman god mercury who was known for being fast and mobile.
  2. The element is not allowed on airplanes because it corrodes aluminum–which is commonly used in aircrafts.
  3. It exists around the world as mercuric sulfide, also known as cinnabar. This creates the pigment known as “vermilion”.
  4. Mercury the only metal that is liquid at room temperature
  5. It is very heavy! In fact, it weighs 13.6 times as much as an equal volume of water.
  6. It was used to treat syphilis until the 20th century. They believed it would cause the patient to salivate the disease out. Side effects included gum ulcers, tooth loss, and death.

Mercury in the Periodic Table

The element mercury, which has symbol Hg and atomic number 80, is a dense liquid metal. It lies to the right of gold and to the left of thallium on the periodic table. Cadmium lies above mercury, and short-lived copernicium lies below it.

Mercury is a group 12 metal along with with zinc and cadmium, however it does not have much in common with them. It is classified as either a transition metal or post-transition metal, depending on who is doing the classification. Mercury has an electron configuration of [Xe]4f145d106s2 .

Where to Find Mercury

Mercury is found rarely in the earth’s crust. It is primarily found in the mineral cinnabar, also known as mercury sulfide. Spain and Italy control about 50% of the world’s supply of cinnabar ores. There are two forms of this that occur in nature. One is red and the other is black. In order to extract the mercury out of the mineral, it must first be heated. Then, the vapor is condensed and collected. Though pretty rare, mercury ores can be found near volcanic regions and hot springs.

Mercury in Today’s World

Vaccinations with Mercury

Mercury has been used in medicine since ancient times. Often, it resulted in poisoning and premature death. As the years have gone on, it has been replaced with safer alternatives. What you may or may not know, is that it is still used in vaccines today. However, it is safe to use. The compound used is called Thimerosal and it’s a preservative. You may be familiar with the modern argument that vaccines cause autism. This is the compound contained in the vaccine on which this claim is disputed. However, there currently exists no scientific evidence to support this. So how much mercury is in a vaccine that contains thimerosal? According to the FDA, the amount of mercury is roughly equivalent to that in a 3-ounce tuna fish can.

Biomagnification of Mercury in Food

If you are a seafood enthusiast, you may be familiar with the term “biomagnification“. This is a process in which harmful substances can bioaccumulate farther up the food chain. Mercury is a stubborn substance as it likes to be absorbed but not excreted. This means it builds up and over time, can lead to serious health complications. So, how are humans involved in this bioaccumulation? We are the consumers of the ocean critters who have accumulated higher mercury levels from their food chain. For example, salmon are on the lower end so they can be consumed often. Trout are a step up and can be eaten a few times a week. However, larger predators such as halibut can only be eaten a few times monthly due to their high levels of mercury.

Toxicity of Mercury

Mercury is very toxic to the human body, and has both acute and long-term effects. Most cases in humans result from consuming fish, or from dental amalgams. There have also been well known public health disasters involving mercury, including thousands of people who died from eating seafood after mercury waste was dumped into Minamata Bay, Japan.

Elemental mercury in liquid form is considered the least toxic, and often can pass through the human body. Vapors, however, are extremely toxic. Mercury (II) salts are considered more toxic than mercury (I) salts, and organo-mercury compounds are the most dangerous, causing the death of chemistry professor Karen Wetterhahn in 1997. Many products are sold to monitor levels of mercury in the environment.

History of Mercury

Though we do not know who discovered mercury, we do know it has been around since ancient times. We know this because the transition metal has been found in various artifacts belonging to the ancient Chinese, Egyptians, Native Americans, Greeks, and more. Historically, it was often used in ancient tombs, medicine, and makeup. One interesting use of the liquid metal was by the second ruler of the Tulunid dynasty in Egypt, Khumarawayh ibn Ahmed ibn Tulun. In a bid to cure his insomnia, he had a lake of mercury created for which he would float on top and fall asleep.

Mercury- compounds, reactions, synthesis, and oxidation states

Amalgams

Mercury is a silvery-white transition metal that can dissolve with other metals to form alloys in a process called amalgamation. It can form amalgams with all metals except iron. One use for amalgams is in dentistry. Dental amalgams consist of mercury paired with trace metals such as silver tin and zinc. They are used to fill cavities and have been used for over 150 years by dentists. It should be noted that whether or not these fillings pose a risk to a certain individual is up to the health care provider.

Compounds

There are two types of compounds of mercury: organic and inorganic. The most common organic compound is methyl mercury, which is extremely toxic. There are no industrial uses for methyl mercury and it is formed naturally in the environment via the methylation of the inorganic mercury ion. The most common inorganic compound is mercuric chloride, HgCl2, which is used in photography, laxatives, disinfectants, fungicides, and more. However, its use has declined in many products so it is mainly found in disinfectants and pesticides. As previously mentioned, mercury exists naturally as mercury sulfide (Cinnabar) which creates the red pigment vermilion.

Reactions

Mercury is very picky with what elements or compounds it will react with. It will not react with dilute acids or non-oxidizing acids. It also prefers to react with compounds and elements that are at a high temperature.

How Mercury is synthesized

As previously stated, mercury is extracted from the mineral cinnabar through the purification process of distillation. This is done by first crushing the ore. It is then heated in a furnace which vaporizes the element. This vapor is then collected and condensed into liquid form. Vaporized mercury is extremely toxic and can wreak havoc on the respiratory system, so it is important to do so with caution.

Elemental mercury can be produced in the lab by reduction of its salts with copper. Cinnabar, mercury (II) sulfide, will decompose into mercury at 580C, but this method produces dangerous mercury vapors that must be safely condensed.

Mercury oxidation states

The transition metal has two main oxidation states: +1 and +2. In the +1 oxidation state, mercury exists as a dimer, the mercurous ion, Hg2+2. It is one of the rarely seen polyatomic anions.

Mercury Physical Properties

  • Symbol: Hg
  • Melting point: -38.9 °C
  • Boiling point: 356.6 °C
  • Density: 13.6 g/mL
  • Atomic weight: 200.59 g.mol -1
  • Atomic number: 80
  • Electronegativity: 1.9
  • Classification: Transition Metal, Group 12 Metal
  • Crustal abundance: 0.05 ppm
  • Electron shell configuration: [ Xe ] 4f14 5d10 6s2
  • Isotopes: 56 total – 7 stable and 33 radioactive
  • Found naturally in cinnabar (HgS)
  • Toxicity: Organic forms of the element are more toxic than inorganic ones. However, inorganic forms can still be physically corrosive and toxic if ingested. The main danger comes form inhaling the vapors.

Where can I buy mercury?

Pure elemental mercury can be purchased from amazon and specialty shops. However, it is toxic so it’s important to be careful with it.

Mercury Beating Heart Chemistry Experiment

Mercury is highly toxic and should be used only with proper training. In the mercury beating heart experiment, mercury is combined with sulfuric acid and an oxidizing agent, creating an oscillating redox reaction that makes the ball of mercury look like a beating heart.

Further Reading