Scandium occurrence

We may note (a) the common occurrence of oxidation state +2 where the 4s electrons have been formally lost, (b) the increase in the number of oxidation states from scandium to manganese in the latter element, the oxidation state + 7 corresponds to the formal loss of the and 3d electrons, (c) the sharp decrease in the number of oxidation states after manganese—suggesting that removal of the paired id electrons is less easy (d) the oxidation state 0, occurring for many of the later elements in the series. ... 

R, C. Vickery, Scandium, yttrium and lanthanum, Chap, 31 in Comprehensive Inorganic Chemistry, Vol. 3, pp, 329-53, Pergamon Press, Oxford, 1973, and references therein, C. T. Horovitz (ed.), Scandium Its Occurrence, Chemistry, Physics, Metallurgy, Biology and Techndlogy, Academic Press, London, 1975, 598 pp. 

Horovitz, C. T., Scandium. Its Occurrence, Chemistry, Physics, Metallurgy, Biology and Technology, p 156. Academic Press, New York, 1975. 

The lanthanides (Ln) include lanthanum (La) and the following fourteen elements—Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu— in which the 4f orbitals are progressively filled. These fifteen elements together with scandium (Sc) and yttrium (Y) are termed the rare-earth metals. The designation of rare earths arises from the fact that these elements were first found in rare minerals and were isolated as oxides (called earths in the early literature). In fact, their occurrence in nature is quite abundant, especially in China, as reserves have been estimated to exceed 84 x 106 tons. In a broader sense, even the actinides (the 5f elements) are sometimes included in the rare-earth family. 

Bernhard F, Walter F, Ettinger K, Taucher J, Mereiter K (1998) Pretulite, SCPO4, a new scandium mineral from the Styrian and lower Austrian lazulite occurrences, Austria. Am Mineral 83 625-630 Boatner LA, Sales BC (1988) Monazite. In Radioactive Waste Forms for the Future. Lutze W, Ewing RC (eds) Elsevier North-Holland, Amsterdam, Ch 8... 

The last comprehensive treatment of scandium as an element and of its alloys and compoimds was given in the book Scandium. Its occurrence, chemistry, physics, metallurgy, biology and technology in 1975 (Gschneidner 1975). Meanwhile numerous... 

There are no data about the interaction of scandium with the alkaline metals. Taking into consideration the large differences in the melting temperatures of Sc and lA elements the occurrence of immiscibility gaps in liquid and solid binary alloys are possible as they occur in the Sc-E (E = alkaline-earth element) alloys (see sect. 2.2). The absence of binary compounds in these systems is very likely. 

Occurrence of three scandium-beryllium intermetallic compounds and their crystal structures are the only data existing about the Sc-Be binary system. Their characteristics are presented in table 2. Gschneidner and Calderwood (1987) reviewed all available papers on scandium-beryllium binary alloys. 

Men kov et al. (1959, 1961) synthesised two scandium tellurides and determined their crystal structures. The data of Men kov et al. (1959) about the cubic y -AhOs-type structure for the compound Sc2Te3 had not been confirmed by a single-crystal structure investigation of that phase performed by White and Dismukes (1965) (see table 12). The latter authors obtained also a specimen of Sc2.3Te3 composition isotypic with Sc2Te3 with the lattice parameters a=4.113, c=4.051 A. This result seems to indicate the occurrence... 

Krupka et al. (1973) observed the occurrence of a solid solution of scandium in the cubic thorium carbide, Th2C3 (ST PU2C3). The lattice parameter changes within the homogeneity range of Th2 o.6Sco-i 4C3 from n = 8.556 to a = 8.563 A, the value for Thi 4Sco.6C3 is n = 8.530 A. 

Chen and Duh (1988) reported the occurrence of the solid solution (Sco-o.2Ri-o.8)2Pei4B at 1000°C and variations of the lattice spacings within its homogeneity range (see table 27). The alloys are ferromagnetic. The Curie temperature of the alloys monotonically decrease with the increasing scandium content (see table 27). 

Occurrence Yttrium is a rare earth element and occurs in nearly all of the rare earth minerals. Rare earths are defined as a group of 17 elements, comprised of scandium, yttrium, and the lanthanides. The similar radii and oxidation states of the rare earths allows liberal substitution of the rare earths for one another into the crystal lattice sites of minerals. This substimtion accounts for their wide dispersion in the earth s crust and the characteristic occurrence as a group of elements within more than 100 minerals. The principal ores of the rare earths are basmasite, monazite, and xenotime. Several of the ores occur in unique geologic settings, whereas others are found in similar occurrences worldwide. 

According to Szabadvary and Evans, pp 55-66 in ref. [17.9] the importance of Nil-son s discovery of scandium surpassed an ordinary" element discovery, as it verified the occurrence of the element to which Mendelejev had given the name eka-boron. 

Occurrence and extraction Applications Physical properties Inorganic and coordination chemistry of the metals scandium to zinc... 

C. T. Horovitz, ed.. Scandium Its Occurrence, Chemistry, Physics, Metalluigy, Biology, and Technology, (Academic Press, London) pp. 111-138 and 323-384. 

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