February 10 , 1840Stockholm, Sweden June 18 , 1905Uppsala, Sweden Per Teodor Cleve, (born Feb. 10, 1840, Stockholm, Swed. died June 18 , 1905 Uppsala) Swedish chemist who discovered the elements holmium and thulium.
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.
At low temperatures, the rare-earth metals holmium (Ho) and erbium (Er) have a nonparallel moment arrangement that gives rise to a substantial spontaneous magnetization.
In that same year Cleve discovered the rare-earth elements holmium and thulium.
Berzelius himself discovered several new elements, including cerium (1803) and thorium (1828), in samples of naturally occurring minerals, and his students discovered lithium, vanadium, lanthanum, didymium (later resolved into praseodymium and neodymium), erbium (later resolved into erbium, ytterbium, scandium, holmium, and thulium), and terbium.
When this is taken into account, the maximum effective magnetic moment is found in dysprosium with holmium a very close second, 10.64 versus 10.60 Bohr magnetons; gadolinium's value is 7.94.
The exceptions are europium, which is bcc from 0 K (−273 °C, or −460 °F) to its melting point at 822 °C (1,512 °F), and holmium, erbium, thulium, and lutetium, which are monomorphic with the hcp structure.
Furthermore, the metals with even atomic numbers (cerium, neodymium, samarium, gadolinium, dysprosium, erbium, and ytterbium) are more abundant than their neighbours with odd atomic numbers (lanthanum, praseodymium, promethium, europium, terbium, holmium, thulium, and lutetium).
On the other hand, the radius of yttrium, 0.9 Å, is nearly the same as that of holmium, 0.901 Å, and this accounts for the presence of yttrium in the heavy lanthanide minerals.
