Argon is a noble gas, commonly used in lighting or storage applications. Its symbol is Ar, as shown by the above picture. Argon, in gas form, is not very common in the atmosphere; however, it one of the most commonly applied gases in industry. Although you don't realise it, Argon gas surrounds you in many forms in your every day life.
Obtaining Argon Gas
For most industrial purposes, pure argon gas is harvested from the air. The process of obtaining argon is called cryogenic distillation. In this process, air from the atmosphere is cooled to a liquid, then slowly let to evaporate at different temperatures. This isolates the different gases in the air by evaporating them at different times, because the evaporation point of each gas in the liquid air evaporates at different temperatures. Along with argon, many other gases are produced at the same time, including oxygen and nitrogen.
Argon is a noble gas, meaning that it has very limited reaction with other elements. Therefore, it occurs as a very pure gas. Because it is a noble gas, it can easily be energised so as to give off light. This is why it, like most noble gases, is used as a light source.
Argon naturally occurs in the gas phase at room temperature. Its boiling is --302.6°F (--185.9°C), just a few degrees from its freezing point of --308.8°F (--199.3°C). At an even colder temperature is Argon's melting point, at 83.8 degrees Kelvin. However, for most of its applications, it is kept in a gas phase, because it is easily stored and energised so as to produce light.
Argon, because of its inability to form bonds with most elements, can be used in a gaseous state in very high temperature industrial applications, such as soldering. Argon can also be used to increase the shelf-life of stored materials because it displaces oxygen, nitrogen and other gases that cause corrosion.
Argon is very dense, at 1.784 grams per litre. It is also soluble in water. As a gas, argon is completely undetectable by sight, smell or taste. Because of its density, argon naturally sinks in relation to air. For example, when argon is stored in an open jar, the jar must be set mouth-up, to contain the gas. Unlike a container of hydrogen, argon will fall out of a jar if it is turned upside-down.
Argon gas is stored in pressurised tanks. When used for lighting purposes, it is kept in glass tubes so that the light emitted by the energised gas can escape. Most argon is also transported in pressurised tanks, where it is placed directly after production.
Argon is an asphyxiant, which is any gas that cannot be breathed instead of oxygen. Argon displaces oxygen, so breathing it in is especially dangerous in closed spaces that are not well ventilated. Finally, argon, when used in lighting applications, must be energised with extremely high voltages. Even though these voltages are at low amperage, touching a part of an argon lamp that is dangerously exposed can be lethal.