Mercury is first described as a liquid in order to provide a comprehensive overview of the element. At room temperature, it is a liquid and one of the 20 least common elements. It is a toxic, metallic element. Mercury is infrequently found free in nature, although it is most commonly found as the red sulfide mineral known as cinnabar, or vermillion. Elemental mercury is a gas at standard atmospheric pressure and temperatures above -38 degrees C.
In terms of behavior, mercury has some characteristics that make it difficult to understand for those not familiar with its properties. Like other liquids, it flows when disturbed. However, if it touches the surface it melts, becoming a sticky mass that does not flow anymore. Then, if you remove the force that was disturbing it, such as lifting it up from below the surface, it will resume its original shape because of its elasticity.
Those are just some examples of how difficult it is to describe what happens to mercury when you change the environment around it. Scientists think about how other substances behave when they are changed by applying concepts from physics to mercury. They do this by measuring how much energy is needed to melt or vaporize small samples of mercury and then comparing these results with predictions based on the physics models.
The most common form of mercury is elemental mercury. It is a colorless, volatile metal that is highly reactive. When exposed to air, it absorbs oxygen to form a thin layer of glass that protects it from further absorption. This makes elemental mercury useful for lighting lamps.
Physical Characteristics At normal temperature, mercury is a silvery-white, gleaming metal.
|Melting point, °C||−38.89|
|Boiling point at 101.3 kPa, °C||357.3|
|Density at 0°C, g/cm3||13.5956|
In reality, all elements, including mercury, may exist in solid, liquid, or gas forms. Furthermore, many chemicals have more than one solid form, with typically extremely diverse characteristics. For example, copper has three solid forms: a bright red metal, used in art; a white metal, used in technology; and an opaque black ceramic, used in science. Each of these materials is used for its unique set of properties, which include hardness, ductility, melting point, etc.
In nature, mercury exists in two solid forms, called elemental mercury and organic mercury. Elemental mercury can be found in volcanic eruptions and other natural sources while organic mercury is derived from animals and plants that have died and decayed. Humans also produce small amounts of organic mercury when they eat fish that have eaten algae containing methylmercury, which is toxic.
In the atmosphere, elemental mercury changes into gaseable mercury, which can condense into droplets that can be carried long distances by wind or rain. Once in water, the mercury vaporizes again.
In the global mercury cycle, elemental mercury is released into the atmosphere from volcanoes and then removed again when it enters the oceans through precipitation or plant uptake. This process continues indefinitely until mercury levels in the environment become too high.
Mercury is both a liquid and a metal at ambient temperature (due to its extremely low melting point of -39C). It is only when cooled that it becomes a solid.
The transition from liquid to solid occurs at approximately 0 degrees Celsius. Liquid mercury can be poured into a glass, but once cooled it will form small spheres that are not malleable. The metal inside a lamp becomes liquid at about 35 degrees Celsius. If you were to touch the bulb after it has been on for a few minutes you would be able to feel its warmth because of the heat produced by the chemical reaction between mercury and oxygen that makes up 90% of a regular household light bulb.
The remaining 10% is made up of other substances such as sulfur, zinc, aluminum, and carbon. These other elements are what give light bulbs their color. If you were to remove these other substances then the mercury would go back into liquid form.
People have used mercury for many things including medicine, photography, and even paint. But people should never eat, drink, or smoke mercury because it is toxic to the human body. Even in very small amounts it can cause serious health problems.
Mercury has a distinct electron configuration that strongly resists electron removal, causing it to behave similarly to noble gas elements. Mercury, as a result, forms weak bonds and is a liquid at ambient temperature. As the metal cools, it becomes a solid with no liquid phase between 100 and 200 °C (212 and 392 °F). Mercury's low melting point makes it useful in thermometers because it does not damage the glass used in thermometer tubes.
The presence of electrons in large numbers causes other problems for mercury use. Most mercury used in industry is obtained from natural sources such as coal or oil shale. These sources contain small amounts of elemental mercury together with other metals and minerals. When burned, these substances release some of their elemental mercury into the air. The amount released depends on how much other metals are present in the source material. Because mercury is toxic, this type of processing should be done under clean room conditions where contamination with other metals is kept to a minimum.
Even when processed under perfect conditions, some residual impurities are always present in manufactured products. For example, coal-fired power plants generate mercury both as elemental mercury and as compounds of mercury such as mercuric chloride. Impurities can bind to these compounds, preventing them from being released into the atmosphere.
Mercury has a melting point of -38.9 degrees Celsius, a boiling point of 356.7 degrees Celsius, and is the only metal that remains liquid at ambient temperature. Droplets of liquid mercury are gleaming and silver-white, with a strong surface tension that makes them look spherical when placed on flat surfaces.
When exposed to air, mercury will gradually evaporate, leaving small particles of elemental mercury that are highly toxic. The particle size decreases as more mercury is evaporated, so even very small amounts of mercury can be harmful if they are inhaled or ingested. There is no known safe level of exposure to elemental mercury.
Elemental mercury is poisonous because it binds to proteins in the body's cells like a heavy metal. This binding prevents the proteins from carrying out their normal cellular functions, which can lead to death. The blood brain barrier makes the brain particularly vulnerable to mercury poisoning; even small amounts of this metal can cause serious problems for young children and adults who cannot escape dangerous levels of exposure.
As mercury vapor is absorbed into the bloodstream through the lungs, it can reach all parts of the body, including the brain and spinal cord. It can also enter cells through the skin or via food chains where it can accumulate in fish and other animals at higher levels than what is considered safe for humans.
The most common source of exposure to elemental mercury is through consumption of seafood that has been contaminated by industrial waste or pesticides.