2019 has been declared by UNESCO as the Year of the Periodic Table. To celebrate, we are releasing a series of blogs about our favourite elements and their importance to the chemical industry. Today’s blog focuses on cobalt and its current and potential uses.

 

History

In 1739, Georg Brandt, whilst studying minerals that gave gave glass a deep blue colour he discovered a new metal, namely cobalt.Today cobalt’s uses vary from health and nutrition to industry. Cobalt is an essential metal, used in the production of alloys to make rechargeable batteries and catalysts. Cobalt is an essential trace element for the human body, an important component of vitamin B12 and plays an essential role in forming amino acids, proteins in nerve cells and in creating neurotransmitters. 

 

 Cobalt is an important component of B12. Image source: flickr: Healthnutrition 

Cobalt and medicine 

The salts found in cobalt can be used as a form of treatment for anaemia, as well as having an important role for athletes acting as an alternative to traditional blood doping. This metal enhances synthesis of erythropoietin, increasing the erythrocyte quantity in blood, and subsequently, improving aerobic performance.

The skin

Cobalt can enter the body via various ways: one way is by the skin. This organ is susceptible to environmental pollution, especially in workers who are employed in heavy industry. 

When cobalt ions from different metal objects repeatedly come into contact with skin, these cobalt ions then diffuse through the skin, causing allergic and irritant reactions.

Important raw material for electric transport

Cobalt is also a critical raw material for electric transport. It is used in the production of the most common types of lithum-ion batteries, thus, powering the current boom in electric vehicles. 

The electric vehicle industry has the potential to grow from 3.2 million in 2017 to around 130 million in 2030, seeing the demand for cobalt increase almost threefold within the next decade.

As the EU continues to develop the battery industry, it is becoming a priority for manufacturing industries to secure adequate cobalt supplies. The electric vehicle boom means cobalt will increase in demand in the EU as well as globally; further projects to monitoring the supply-and-demand situation will be announced.

2019 has been declared by UNESCO as the Year of the Periodic Table. To celebrate, we are releasing a series of blogs about our favourite elements and their importance to the chemical industry. Today’s blog is about iodine and some of the exciting reactions it can do!

Iodine & Aluminium

 

Reaction between iodine and aluminum. These two components were mixed together, followed by a few drops of hot water. Source: FaceOfChemistry

Reactions between iodine and group 2 metals generally produce a metal iodide. The reaction that occurs is:

2Al(s) + 3I2(s) → Al2I6(s)

Freshly prepared aluminium iodide reacts vigorously with water, particularly if its hot, releasing fumes of hydrogen iodide. The purple colour is given by residual iodine vapours.

Iodine & Zinc

 

Zinc and iodine react similarly to aluminium and iodine. Source: koen2all

Zinc is another metal, and when it reacts with iodine it too forms a salt – zinc iodide. The reaction is as follows:

Zn + I2→ ZnI2

The reaction is highly exothermic, so we see sublimation of some of the iodide and purple vapours, as with the aluminium reaction. Zinc iodide has uses in industrial radiography and electron microscopy. 

Iodine & Sodium

 

Iodine reacting with molten sodium gives an explosive reaction that resembles fireworks. Source: Bunsen Burns

As with the other two metals, sodium reacts violently with iodine, producing clouds of purple sublimated iodine vapour and sodium iodide. The reaction proceeds as follows:

Na + I2→ 2NaI

Sodium iodide is used as a food supplement and reactant in organic chemistry.

Iodine Clock reaction

 

The iodine clock reaction – a classic chemical clock used to study kinetics. Source: koen2all

The reaction starts by adding a solution of potassium iodide, sodium thiosuphate and starch to a mixture of hydrogen peroxide and sulphuric acid. A set of two reactions then occur.

First, in a slow reaction, iodine is produced:

H2O2 + 2I− + 2H+ → I2 + 2H2O

This is followed by a second fast reaction, where iodine is converted to iodide by the thiosulphate ion:

2S2O32− + I2 → S4O62− + 2I−

The reaction changes colour to a dark blue or black.

Elephants toothpaste

 

The elephant’s toothpaste reaction is a favourite for chemistry outreach events. Source: koen2all

In this fun reaction, hydrogen peroxide is decomposed into hydrogen and oxygen, and catalysed by potassium iodide. When this reaction is mixed with washing-up liquid, the oxygen and hydrogen gas that is produced creates bubbles and the ‘elephant’s toothpaste’ effect.

There are lot’s of fun reactions to be done with iodine and the other halogens (fluorine, bromine, chlorine). 

Iodine’s sublimation to a bright purple vapour makes it’s reactions visually pleasing, and great fun for outreach events and science classes.