Xenotime YPO

Of all the 17 rare-earths in the lanthanide series, terbium is number 14 in abundance. Terbium can be separated from the minerals xenotime (YPO ) and euxenite, a mixmre of the following (Y, Ca, Er, La, Ce, Y, Th)(Nb, Ta, Ti O ). It is obtained in commercial amount from monazite sand by the ion-exchange process. Monazite may contain as much as 50% rare-earth elements, and about 0.03% of this is terbium. 

The chief rare-earth ores are the mixed phosphate minerals monazite [(CeLaYTh)PO, monochnic] and xenotime [YPO, tetragonal], found in heavy mineral sand deposits, and the fluorocarbonate bastnaesite [(Ce,La)(C03)F, hexagonal], which occur in carbonatites and... 

M20 Xenotime YPO from Ytterby, Sweden. Tetragonal. Reddish-brown vein in pegmatite. 

Raman spectroscopy has been used in studies of the rare earth orthophosphates (table 4). The spectra are described by Richman (1966), and the normal coordination analysis calculations of the vibrations of free PO ion in xenotime structure are presented by Mooney and Toma (1967). Lazarev et al. (1978) have calculated the normal coordinates of YPO crystals and have shown that the resonance splitting of the frequencies of internal vibrations of the complex anion cannot be due to dipole-dipole interaction of the localized vibrators. Begun et al. 

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