Even the two rarest (thulium and lutetium) are more abundant in the Earth's crust than gold or platinum.A decade ago America was the world's largest producer of rare-earth metals.
Though lutetium composes only trace mounts (less than 0.1 percent by weight) of the commercially important minerals bastnasite and monazite, it has proved feasible to extract the metal as a by-product.
The element behaves as a typical rare earth, forming a series of compounds in oxidation state +3, such as lutetium sesquioxide, sulfate, and chloride.
Hydrogen is absorbed at high temperatures by many transition metals (scandium, 21, through copper, 29; yttrium, 39, through silver, 47; hafnium, 72, through gold, 79); and metals of the actinoid (actinium, 89, through lawrencium, 103) and lanthanoid series (lanthanum, 57, through lutetium, 71) to form hard, alloy-like hydrides.
Yttria, the first rare earth to be discovered, turned out to be a mixture of oxides from which, over a span of more than a century, nine elements yttrium, scandium (atomic number 21), and the heavy lanthanide metals from terbium (atomic number 65) to lutetium (atomic number 71)—were separated.
The periodic table of the elements contains all of the chemical elements that have been discovered or made; they are arranged, in the order of their atomic numbers, in seven horizontal periods, with the lanthanoids (lanthanum, 57, to lutetium, 71) and the actinoids (actinium, 89, to lawrencium, 103) indicated separately below (unless otherwise stated, Figure 1 will be used as reference).
The most stable complex comes out first i.e., the copper or zinc complex, followed by lutetium, ytterbium, the other lanthanides (and yttrium, which usually comes out in the vicinity of dysprosium and holmium, depending upon the complexing agent), and finally lanthanum.
Furthermore, a close examination of these elements reveals vast differences in their behaviours and properties; e.g., the melting point of lanthanum, the prototype element of the lanthanide series (918 °C, or 1,684 °F), is much lower than the melting point of lutetium, the last element in the series (1,663 °C, or 3,025 °F).
The last naturally occurring rare-earth element (lutetium) was discovered in 1907, but research into the chemistry of these elements was difficult because no one knew how many true rare-earth elements existed.
This continues until the 14th electron is added at lutetium, where all the 4f electron spins are paired up, and lutetium has no 4f magnetic moment.
