Yttrium orthorhombic compound

From Dy to Tm, there are no intermediate compounds but only narrow solid solutions of the spinel-type from 10283. With Yb, the homogeneity range is larger and exists from 10283 to YbInS3 (Abdullaev et al., 1968). Finally, with yttrium an orthorhombic compound YInS3 has been described (Karaev et al., 1966b). 

Samarskite occurs in the Ural Mountains, Mitchell County (North Carolina, U.S.A.), Canada, and India. The tantalum content is often small, sometimes nil, and the rare earth oxides, chiefly yttria and ceria, are usually present in considerable number and proportions. The ore is radioactive and contains helium. It forms black, orthorhombic crystals. The density varies from 4-2 to G-2.5 It has been suggested that the niobium and tantalum are disintegration products of compounds of yttrium and cerium with the two higher homologues of manganese,4 masurium, and rhenium. 

As already mentioned the tervalent melal isopropoxides were shown to be pentanuclear oxo-isopropoxides [M5(/Li5-0)(/r3-OPr )4(OPr )5] with the square pyramidal structure for the M5O14 core (Fig. 5.5). Structures have been reported for M = Y, Pr, Yb, and In, and also for the heterometallic compound in which the two metals were distributed randomly over the five sites [Y4PrO(OPr )i3]. Although single crystals of [Er5(/u,5-0)(/r3-OPr )4(/u,-OPr )4(OPr )5] could not be obtained, the X-ray powder diffraction data showed that it was isomorphous and isostructural with Pr, Yb, and In compounds which are all monoclinic P2i/n (cf. the yttrium compound which is orthorhombic). Interestingly neodymium formed the pentanuclear complex [Nd5(/i5-0)(/r,3-OPr )2(/i-OPr )6(OPr )5(I OH)2] in which the fi5-oxo ligand is at the centre of a trigonal bipyramid of Nd atoms. ... 

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