Tungsten

Tungsten is a type of chemical element that has a symbol W and an atomic number 74. Tungsten element is amongst the rare metals that are occurring naturally on the Earth and is almost exclusively combined with several other elements in the chemical compounds rather than being alone. It was identified as a newer element in the year 1781 and was first isolated as a metal in the year 1783. Its important ores are wolframite and scheelite. Tungsten has many alloys that have numerous applications which include the incandescent light bulb filaments, X-ray tubes (as both the filament and target), the electrodes in the gas tungsten arc welding, the superalloys, and radiation shielding. Tungsten's hardness and high density also give it some military applications in the penetrating projectiles. Tungsten compounds are also used often as the industrial catalysts. In this article, we will learn about tungsten in detail which includes the tungsten melting point, boiling point, tungsten uses, tungsten properties, and the applications of tungsten.

What is Tungsten?

Tungsten is also known as wolfram, and along with Cr and Mo, it belongs to group 6 of the periodic table. The element tungsten has the atomic number of 74 and the atomic mass of 184. Its two main oxidation states are +4 & +6 and it has five different stable isotopes that are 180 W, 182 W, 183 W, 184 W, and 186 W amongst which 182 W, 184 W, and 186 W are found to be the most abundant at 26.498%, 30.64%, and 28.426% respectively.

Tungsten is much similar to molybdenum chemically and its chemistry is one the most complex amongst the transition elements.

Tungsten is a rare element and has a crystal abundance of around 1.0–1.5 mg kg-1 which is similar to that of its neighbouring elements present in the periodic table, molybdenum.

Tungsten is a strong lithophile element, even though it is a siderophile in the iron meteorites and is markedly less chalcophile than the element molybdenum.

Apart from the sulfides, the element occurs as the W⁴⁺ cation in the rare mineral tungstenite.

Tungsten also has essentially anionic geochemistry which is based on the tungstate WO₄²⁻ ion, wherein the W₆⁺ ion is present in the four- or six-fold coordination.

Let us now look at the physical properties of tungsten and the chemical properties of tungsten in detail.

Properties of Tungsten

Tungsten Uses

Some of the applications of tungsten are as follows:

1. Tungsten is an economically important metal which is being widely used in the light-bulb filaments, electron and television tubes, several abrasives and special alloys just as steels tool.

2. Tungsten carbide has a great importance in the metal-works, mining and petroleum industries. Contamination from these sources is therefore possible in industrial and urban areas.

3. Evidence for the significant biological role for tungsten is not much, which is in contrast to molybdenum, that is an essential trace element, although some minor concentrations in some plants suggest a specialized function that perhaps substitutes molybdenum if there is a deficiency.

4. There is a limited ecotoxicity data available that anything higher than the trace amounts of tungsten in solution is usually considered to be toxic.

Effects of Tungsten

Since tungsten is a rare metal and its compounds are usually inert, the effects of tungsten on the environment are much limited. The abundance of tungsten in the crust of the Earth is known to be around 1.5 parts per million. It is one of the more rare elements that is found on Earth.

Tungsten was at first believed to be a relatively inert element and an only slightly toxic metal, but at the beginning of the year 2000, the risk presented by the tungsten alloys, its dust and particulates to lead to cancer and several other adverse effects in animals as well as humans have been known from the in vitro and in the vivo experiments. The median lethal dose LD50 is dependant strongly on the animals and the method of administration and varies between 59 mg/kg in intravenous, rabbits and 5000 mg/kg in the tungsten metal powder, intraperitoneal rats. People can be exposed to tungsten even in the workplace by breathing it in, swallowing it, skin contact, and eye contact.