| This element is found in almost all rare-earth minerals and in uranium ores but is never found in nature as a free element. Yttrium is commercially recovered from monazite sand (3% content, [(Ce,
La, etc.)PO4]) and from bastnasite (0.2% content, [(Ce, La, etc.)(CO3)F]). It is commercially produced by reducing yttrium fluoride with calcium metal but it can also be produced using other techniques. It is difficult to separate from other rare earths and when extracted, is a dark gray powder. The original "rare earths" ceria (1803) and yttria (1794) reflect the great geochemical
divide that occurs between the light and heavy lanthanoids due to "lanthanoid contraction". The lighter lanthanoids, with
a larger radius, partition into minerals in sites with a higher coordination number (e.g. monazite), whereas the smaller heavy
lanthanoids prefer a slightly lower coordination number (as in xenotime). The lighter lanthanoids are also more relatively
abundant in the Earth's outer crust than the heavies, relative to the abundance in chondritic meteorites, due to size fractionation.
Yttrium falls into the middle of the heavy group in size, and thus inevitably occurs with these in minerals, where it comprises
about two-thirds of the mixed oxides by weight. This composition is typical of gadolinite, xenotime, and certain ion adsorption clays currently mined in the south of China.
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Occurrence