Neodymium

Neodymium is a chemical element. Its official symbol is Nd, and its atomic number is 60, which means it has 60 protons in its nucleus.

The element was discovered by Austrian chemist Baron Carl Auervon Welsbach in a roundabout way. Welsbach’s original elemental ‘discovery’ was didymium – a material he thought was an element. It even had the symbol Di in Mendeleev’s 1869 version of the periodic table of elements. Welsbach later separated the material into two elements – neodymium and praseodymium. The name neodymium comes from the Greek word neos (meaning new) and didymos (meaning twin). Praseodymium means green twin. The elements are so similar that they are next to each other on the periodic table.

Rare-earth elements

Neodymium is one of the 17 elements known as rare-earth elements. The rare-earth elements occur together on the periodic table. Fifteen of the elements, numbered 57–71, are in the row that sits under the main table. (This row is also called the lanthanide series.) Two more elements – scandium and yttrium – have similar chemical properties so they are also called rare-earth elements.

The rare-earth elements aren’t really all that rare. In the 18th and 19th centuries, materials were called ‘earths’ if they could not be changed further by heating them up. ‘Earths’ like magnesium were relatively easy to find. The rare-earth elements are dispersed or ‘sprinkled’ in ore deposits, rather than occurring as free elements or concentrated in minerals. At the time, they were difficult to locate so they were considered rare.

Neodymium is fairly common – it’s about as abundant as zinc and copper. However, it is dispersed throughout the Earth’s crust, with small amounts found here and there. Neodymium, like most rare-earth elements, is often a byproduct from other mining operations. If it is found with other rare-earth elements that are chemically similar, it becomes a complex process and a considerable expense to separate them. In 2019, a metric ton of neodymium oxide costs more than NZ$160,000! Compare that to NZ$4,000 for zinc and NZ$10,000 for copper. In spite of the price, neodymium and other rare-earth elements are in huge demand.

Uses of neodymium

Neodymium compounds were first used to colour glass. Its properties cause the colour of the glass to change from purple to yellow to blue or green under different lighting conditions. We still use neodymium compounds in glass products today – to whiten the light in incandescent bulbs and to make goggles for welders and glass blowers.

The real demands for neodymium are in products likely to be found in your pocket and throughout the classroom. Neodymium, iron and boron (NIB) combine to create very powerful magnets. A 1 g NIB magnet can hold up a 1.3 kg iron sphere! Tiny NIB magnets are found in cell phones, earbuds, computer hard drives and DVD and CD players. Larger NIB magnets are used in the electric motors of hybrid and electric vehicles and in some wind turbines. NIB magnets are also used to identify counterfeit money. Real paper money has tiny magnetic particles added to the inks when they are printed.

NIB magnets and toys

Neodymium magnets are exceptionally strong. They have a very strong attraction to one another and can move considerable distances and at great speed. There are reports that people have had fingers crushed when caught between two magnets.

Magnetic building sets with rods and balls have been redesigned to make them safer to use. The tiny, strong neodymium magnets make the building sets lots of fun, but if the magnets come loose, they can be dangerous if swallowed. The magnets attract each other and can cause tears in the stomach and intestines.