The rare-earth elements (REE) are naturally occurring non-toxic materials, whose unique properties make them essential to emerging technologies that contribute to environmental, energy efficiency and health solutions. REE's consist of 16 elements, being the 15 lanthanide-series elements plus the metal yttrium. The REE's are grouped together as they display similar chemical properties, in particular the ability to readily discharge and accept electrons, making them indispensable and non-replaceable in many electronic, optical, magnetic and catalytic applications.
In addition to REE's, Tasman Metals Ltd is exploring for the metals scandium, zirconium, hafnium, niobium and tantalum which display unique and highly sought chemical properties.
REE's and scandium, zirconium, hafnium, niobium and tantalum are considered strategic metals by Tasman due to the essential role they play in high technology and defence applications, along with their irreplaceable chemical behaviour. Securing the supply of strategic metals has been identified by governments as critical to ensure the development and growth of capital intensive technology and green industries.
Despite their name, the REE are in fact not especially rare. Each is more common in the earth's crust than silver, gold or platinum, while cerium, yttrium, neodymium and lanthanum are more common than lead. Thulium and lutetium are the least abundant REE's with crustal abundance of approximately 0.5 parts per million. REE's are never found as free metals in the earth's crust and all their naturally occurring minerals consist of mixtures of various REE's with other metals and non-metals.
REE are classified into two subgroups, as LIGHT RARE EARTH ELEMENTS (LREE) comprising the first five elements (atomic numbers 57-62) ; and the HEAVY RARE EARTH ELEMENTS (HREE), comprising the elements with atomic numbers 63-71 as well as yttrium. Despite its low atomic weight, yttrium is classified with the HREE because its properties are closer to those of the HREE subgroup than to LREE.
For an interactive look at the elements in the periodic table including the rare earth elements, please follow this link