Gadolinium europium holmium lanthanide

The lanthanide or rare earth elements (atomic numbers 57 through 71) typically add electrons to the 4f orbitals as the atomic number increases, but lanthanum (4f°) is usually considered a lanthanide. Scandium and yttrium are also chemically similar to lanthanides. Lanthanide chemistry is typically that of + 3 cations, and as the atomic number increases, there is a decrease in radius for each lanthanide, known as the lanthanide contraction. Because bonding within the lanthanide series is usually predominantly ionic, the lanthanide contraction often determines the differences in properties of lanthanide compounds and ions. Lanthanide compounds often have high coordination numbers between 6 and 12. see also Cerium Dysprosium Erbium Europium Gadolinium Holmium Lanthanum Lutetium Praseodymium Promethium Samarium Terbium Thulium Ytterbium. 

In another series of studies of the soluble lanthanide chlorides, rats were fed gadolinium, samarium, terbium, thulium, ytterbium, praseodymium, neodymium, lutetium, europium, dysprosium, holmium, and erbium chloride in their diet at doses of 0, 5, 50, and 500 mg kg day for 12 weeks. Only ytterbium chloride caused any significant effect, with the 500 mg kg dose causing gastric hemorrhages. The other lanthanides caused no adverse effects at the maximum 500 mg kg dose. 

Once again, crystal structure data are necessary in order to show how the lanthanides bind in proteins. With the help of D. C. Philhps group (Oxford), we have made a start with lysozyme showing that Gd binds between the two carboxylate groups—t.e., exactly at the active site. We 42) have done NMR studies on several diflFerent cations of the lanthanide series to discover which is most useful. Gadolinium (broadening-probe), europium, and holmium (shift-probes) have much... 

Cerium, Praeseodymium, Neodymium, Promethium, Samarium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium, Lutecium, These are the transition elements, and are also called the Lanthanides. Actinium... 

The rare earth minerals are composed of scandium, yttrium, and the lanthanides. The lanthanides comprise a group of 15 elements that include lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. Cerium is the most abundant element in the rare earth group at 60 ppm, followed by yttrium at 33 ppm, lanthanum at 30 ppm, and neodymium at 28 ppm. Thulium and lutetium are the least abundant at 0.5 ppm. 

An early classification of the rare earths (the oxides of lanthanides) in relation to their separation from ores, was in the ceritic earths (the oxides from lanthanum to samarium) and yttric earths (from europium to lutetium, but also scandium and yttrium). A further refinement of analytical methods made it possible to split the yttric earths into terbic (europium, gadolinium, terbium), erbic (dysprosium, holmium, erbium, thulium), and ytterbic (ytterbium and lutetium) earths, along with yttrium oxide and scandium oxide. 

The only complexes of lanthanum or cerium to be described are [La(terpy)3][C104]3 175) and Ce(terpy)Cl3 H20 411). The lanthanum compound is a 1 3 electrolyte in MeCN or MeN02, and is almost certainly a nine-coordinate mononuclear species the structure of the cerium compound is not known with any certainty. A number of workers have reported hydrated 1 1 complexes of terpy with praseodymium chloride 376,411,438), and the complex PrCl3(terpy)-8H20 has been structurally characterized 376). The metal is in nine-coordinate monocapped square-antiprismatic [Pr(terpy)Cl(H20)5] cations (Fig. 24). Complexes with a 1 1 stoichiometry have also been described for neodymium 33, 409, 411, 413, 417), samarium 33, 411, 412), europium 33, 316, 411, 414, 417), gadolinium 33, 411), terbium 316, 410, 414), dysprosium 33, 410, 412), holmium 33, 410), erbium 33, 410, 417), thulium 410, 412), and ytterbium 410). The 1 2 stoichiometry has only been observed with the later lanthanides, europium 33, 411, 414), gadolinium, dysprosium, and erbium 33). 

Lanthanide elements (referred to as Ln) have atomic numbers that range from 57 to 71. They are lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu). With the inclusion of scandium (Sc) and yttrium (Y), which are in the same subgroup, this total of 17 elements are referred to as the rare earth elements (RE). They are similar in some aspects but very different in many others. Based on the electronic configuration of the rare earth elements, in this chapter we will discuss the lanthanide contraction phenomenon and the consequential effects on the chemical and physical properties of these elements. The coordination chemistry of lanthanide complexes containing small inorganic ligands is also briefly introduced here [1-5]. 

Scheele suggested that lanthanides could be classed, as could actinides, in new kinds of groups, c, as follows Ic thulium [as a homologue of rubidium (la) and silver (Ib)] lie ytterbium IIIc lutetium IVc cerium, praseodymium, neodymium (as homologues of zirconium) Vc promethium Vic samarium VIIc europium VIIIc gadolinium, terbium, dysprosium, holmium, erbium (as homologues of ruthenium, rhodium, and palladium). 

---