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The crystallization conditions of Al2(WO4)3 from Li2O-WO3 solvents (molar ratio 30.0:70.0, 32.5:67.5, 35.0:65.0,
45.0:55.0 and 55.0:45.0) as well as from Na2O-WO3 solvents (molar ratio 25.0:75.0, 27.5:72.5, 30.0:70.0 and 32.5:67.5)
have been investigated. The concentration and temperature regions of crystallization of Al2(WO4)3 and the density,
viscosity as well as the solution losses due to evaporation have been established. On the basis of the data obtained it has
been concluded that the most suitable solvent for growing Al2(WO4)3 single crystals is Na2O-WO3 with a molar ratio of
27.5:72.5.
The temperature and concentration regions of crystallization of Al2-xMex(WO4)3 solid solutions obtained by replacement
of Al2O3 in the Na2O-Al2O3-WO3 system by Ga2O3, In2O3, Sc2O3 or Y2O3 have been investigated. The crystallization
regions and concentration boundaries of existence of the solutions are found to depend strongly on the nature of the
replacing element. Solid solutions containing Sc and In crystallize from high-temperature solutions with a lower
concentration as compared to that of pure Al2(WO4)3, this being accompanied by a high distribution coefficient of the
substituting ion. On the contrary, Ga and Y containing solid solutions crystallize from high-temperature solutions with
much higher concentrations, the distribution coefficient of the substituting ions being relatively low. The experimental
obtained data are the basis for growing bulk single crystals with preset compositions from the Al2-X MeX (WO4)3, Me=Sc, Y, Ga or In, solid solutions.
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