Aluminum orthophosphate crystals

Hydrothermal recrystallization is not conhned to quartz. Some II-VI compounds, such as ZnSe, ZnTe, CdSe, and CdTe, have also been recrystallized into large single crystals using the technique (Kolb, 1968), as well as aluminum orthophosphate, AIPO4 (Kolb, 1980). The technique can also be used preparatively as in the case of potassium titanyl phosphate (Laudise et ah, 1986) ... 

Fig. 6. Parts of the crystal structures of acidic aluminum orthophosphates (polyhedral representation), (a) Al(Fl2P04)3-C (b) Al(Fl2P04)3-A. One structural unit of Al(Fl2P04)3-C is indicated by shading. The hydrogen atom positions are shown by wedges [reprinted with permission from Kniep (14) copyright 1986 Wiley-VCFI].

Scandium orthophosphate contains two water molecules and is isomorphic with the corresponding iron and aluminum compounds having an orthorhombic crystal lattice (Komissarova et al., 1965a Eshchenko et al., 1979). 

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