Yttrium, lanthanum, lanthanides

LB7I12, Ln = Tb, Er, Lu Erylie. BWs instr.— chains of oct, cluster [LngHalia] 

CaTiOa ste type MLn2Clg, chains of single-cap antiprism [LnCl7] and [LnClg], NaEugClg 22,25) 

La2Brs,blk. PT2Hid5 NdsQy EU4CI9 SnigBrii YbaFy 

Turova, Inorganic Chemistry in Tables, DOI10.1007/978-3-642-20487-6 27, Springer-Verlag Berlin Heidelberg 2011 

MjLnOa, LigILnOsJ, Ln = Ce, Pr, Tb OgTb207, MifiTbaOw, in str. - chains oftetT.pyram. 

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Scandium is very widely but thinly distributed and its only rich mineral is the rare thortveitite, Sc2Si20v (p. 348), found in Norway, but since scandium has only small-scale commercial use, and can be obtained as a byproduct in the extraction of other materials, this is not a critical problem. Yttrium and lanthanum are invariably associated with lanthanide elements, the former (Y) with the heavier or Yttrium group lanthanides in minerals such as xenotime, M "P04 and gadolinite, M M SijOio (M = Fe, Be), and the latter (La) with the lighter or cerium group lanthanides in minerals such as monazite, M P04 and bastnaesite, M C03F. This association of similar metals is a reflection of their ionic radii. While La is similar in size to the early lanthanides which immediately follow it in the periodic table, Y , because of the steady fall in ionic radius along the lanthanide series (p. 1234), is more akin to the later lanthanides. 

Table 30.5 Stoichiometries and structures of reduced halides (X/M < 2) of scandium, yttrium, lanthanum and the lanthanides...

The yttrium, lanthanum and other lanthanide salts exploded after dehydration during heating to above 300°C. 

The 3rd group of the Periodic Table (the 1st column within the block of the transition elements) contains the metals scandium, yttrium, lanthanum, and actinium. Lanthanum (atomic number 57) may be considered the earliest member of the family of metals, called lanthanides (general symbol Ln), forming, inside the principal transition series, an inner transition series (up to atomic number 71). Scandium and yttrium together with the lanthanides are also called rare earth metals (general symbol R). 

The analytical chemistry of the transition elements see Transition Metals), that is, those with partly filled shells of d (see (f Configuration) or f electrons see f-Block Metals), should include that of the first transition period (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, and Cu) and that of the second transition series (Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, and Ag). The third transition series embraces Hf, Ta, W, Re, Os, Ir, Pt, and An, and although it formally begins with lanthanum, for historical reasons this element is usually included with the lanthanoids (rare-earth elements) see Scandium, Yttrium the Lanthanides Inorganic Coordination Chemistry Rare Earth Elements). The actinoid elements see Actinides Inorganic Coordination Chemistry) are all radioactive see Radioactive Decay) and those with atomic number see Atomic Number) greater than uranium (Z = 92) are artificial the analytical chemistry of these elements is too specialized to consider here. 

IV. Chalcogenocyanate Complexes of the Transition Elements A. Scandium, Yttrium, Lanthanum, and the Lanthanides i. Cyanates... 

A t the time of Alfred Werner s birth, the only lanthanide elements that had been identified positively were lanthanum and cerium. Yttrium, a lanthanide element by all criteria except electronic configuration, was known also. However, in 1891 when Werner proposed the substance of the coordination theory, all of the elements of the lanthanide series except promethium, europium, and lutetium had been clearly identified and quite well characterized. Only promethium remained undiscovered at the time of Werner s demise. 

Mores LS (1976) Thermochemical properties of yttrium, lanthanum, and lanthanide elements and ions. Chem Rev 76 827-841... 

This chapter centers on the determination of enthalpies of formation of pure rare earth binary oxides at 298.15 K. Inasmuch as possible, the other properties and the properties at temperatures other than 298.15 K are also presented. In this chapter the rare earths are considered to be yttrium, lanthanum, and the lanthanide elements Ce-Lu. The thermochemistry of scandium oxides is not treated in this chapter. 

The rare earths are divided into the lanthanide group, and the elements scandium and yttrium. The lanthanides constitute a special group of elements that have an atomic structure different from the other elements, although they are somewhat akin to the actinide series. The lanthanides make up a group of elements ranging from atomic number 57 (lanthanum) to 71 (lutetium). They are all very similar to lanthanum, which is the reason for the name lanthanide. The other two rare earths, scandium and yttrium, are somewhat apart from the lanthanide series, and will be treated separately. 

Morss, L.R., 1985, Yttrium, lanthanum and the lanthanide elements, in Standard Potentials in Aqueous Solution, eds A.J. Bard, R. Parsons and J. Jordan (Marcel Dekker, New York) pp. 587-629. 

In this article the term organometallic compound includes alkyl and aryl derivatives of the rare earths—the transition metals of group III, scandium, yttrium, lanthanum and the lanthanides cerium to liitetium with covalent metal-to-carbon a-bonds, as well as the so-called 77-complexes with more than monohapto metal-to-carbon bonds, for example cyclopentadienyl and olefin complexes, metal acetylides, but not carbonyls, cyanides and isocyanide complexes. Derivatives of scandium, yttrium and lanthanum are included and discussed together with the compounds of the lanthanides, because of many similarities in the synthesis and the chemistry of these organometallic derivatives of the rare earths. 

Tricyclopentadienyl rare earth compounds form stable 1 1 adducts with many bases. THF adducts have been described for yttrium, lanthanum and nearly all lanthanides (Manastyrskyj and Dubeck, 1964 Calderazzo et al., 1966 E.O. Fischer and H. Fischer, 1966 R.D. Fischer and H. Fischer, 1967 Pappalardo, 1969 Raymond and Eigenbrodt, 1980 Rogers et al., 1981 Deacon et al., 1982). Tetrahydrofuran can be removed in high vacuum from all the complexes except for... 

Horss, L. R. Thermochemical Properties of Yttrium, Lanthanum, and the Lanthanide Elements and Ions... 

Volume 22 T. Mioduski and M. Salomon, Scandium, Yttrium, Lanthanum and Lanthanide Halides in... 

The elements in the group III B scandium, yttrium, lanthanum and actinium that have an incompletely filled d subshell in their atomic state (n - l)d ns. Although both lanthanum and actinium could be included in the d transition metal series, they are very similar physically and chemically to the elements in the f-block and therefore are considered to be f-type transition elements (4f-, 5f-type transition elements, respectively). The last element of the lanthanides series, lutetium, also has a partly filled d orbital (Table 2.6) and could also be included in the d transition metal group. However, it has similar properties to the 4f-type transition metals, where it is usually grouped with lanthanum and the rest of the lanthanides series. 

Scandium, Yttrium, Lanthanum and the 14 Lanthanides -Rare Earth Metals (REMs)... 

Yttrium, Lanthanum and the Lanthanides. P NMR spectroscopy has been used to study complexation of La " by (4-02NC6H40)2P02H and (MeO)(4-02NC6H40)P02H. C and N NMR spectroscopy has been used to study complex formation between [SCN] andPr + and Nd. P chemical shifts of di(chlorophenyl)dithiophosphinic acid correlate quantitatively with the extrac-tability of Am and Eu ". ... 

The absorption spectra of the lanthanide ions are quite characteristic of the individual lanthanides. Scandium, yttrium, lanthanum, and lutetium do not absorb in the spectral region from 200-1000 nm. The remaining lanthanides all absorb in this region, although the molar absorptivities of even the most intense bands are less than 12 /mole cm as is shown in table 37A.1. 

The luminescence properties of trivalent lanthanide ions in rare earth silicate matrices are quite well known. Most materials studied include oxyortho-, di-, halo-and alkali double silicates of yttrium, lanthanum, gadolinium and lutetium. 

It may be helpful to explain the use of the terms rare earths and lanthanides throughout the text. By convenience, the term lanthanides refers to the elements La (Z = 57) to Lu (Z = 71). The term rare earths is commonly used for the lanthanides with inclusion of the elements Y (Z = 39) and Sc (Z = 21). Although one speaks often about rare-earth spectroscopy, the term lanthanide spectroscopy is preferable. The main objects of study in lanthanide spectroscopy are the trivalent lanthanide ions from Ce (4f ) to Yb3+ (4f ), since these ions have unpaired f electrons and can interact with ultraviolet, visible or near-infrared radiation. Divalent ions like Eu " " have gained less interest and will not be discussed here. The trivalent lanthanide ions La " (4f ) and Lu (4f ) are not spectroscopically active, because of an empty or filled 4f shell. The same is true for and Sc. Yttrium, lanthanum and to a lesser extent lutetium compounds are used as transparent host crystals in which other trivalent lanthanide ions can be doped. The trivalent lanthanide ions can readily substitute for Y, La " and Lu. Expressions like point group of the rare-earth site and the crystal field in rare-earth compounds are thus meaningful. 

Lanthanide compounds such as yttrium and lanthanum alkoxides have been reported to yield high-molecular-mass polyesters under mild conditions. The yttrium alkoxide-initiated polymerization of CL proceeded rapidly at room temperature [27-29], while the use of bulky groups reduced the transesterification reaction such that polymers with a narrow molecular mass were obtained (Scheme 11.3). For example, the bulky phenoxide ligands of the yttrium or lanthanide catalyst were exchanged for the smaller alcohol (2-propanol), followed by coordination and insertion of the monomer (CL) [27]. 

Reference has been made already to the existence of a set of inner transition elements, following lanthanum, in which the quantum level being filled is neither the outer quantum level nor the penultimate level, but the next inner. These elements, together with yttrium (a transition metal), were called the rare earths , since they occurred in uncommon mixtures of what were believed to be earths or oxides. With the recognition of their special structure, the elements from lanthanum to lutetium were re-named the lanthanons or lanthanides. They resemble one another very closely, so much so that their separation presented a major problem, since all their compounds are very much alike. They exhibit oxidation state -i-3 and show in this state predominantly ionic characteristics—the ions. 

Lanthanides is the name given collectively to the fifteen elements, also called the elements, ranging from lanthanum. La, atomic number 57, to lutetium, Lu, atomic number 71. The rare earths comprise lanthanides, yttrium, Y, atomic number 39, and scandium. Sc, atomic number 21. The most abundant member of the rare earths is cerium, Ce, atomic number 58 (see Ceriumand cerium compounds). 

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