Phase Relations in the Systems A 2 O‐Metal Oxide‐WO 3 (A=Li, Na; Metal=Fe, Cr, Sn, Zr, Th, V)

Phase relations, with special emphasis on the formation of wolframite‐type phases, were determined in 12 ternary systems, each containing an alkali oxide (Li 2 O, Na 2 O), a polyvalent oxide (Fe 2 O 3 , Cr 2 O 3 , SnO 2 , ThO 2 , ZrO 2 , V 2 O 5 ), and WO 3 . Among 12 ternary phases characterized, 5 have the wolframite‐type structure. They are LiFe(WO 4 ) 2 , LiCr(WO 4 ) 2 , NaFe(WO 4 ) 2 , NaCr(WO 4 ) 2 , and Li 2 Zr(WO 4 ) 3 . Complete series of solid solutions exist along Li(Fe,Cr) (WO 4 ) 2 and Na(Fe,Cr)(WO 4 ) 2 joins but not along other wolframite joins. Both LiFe(WO 4 ) 2 and LiCr(WO 4 ) 2 were also found to form complete solid solution series with MgWO 4 , a compound used hi this study to represent the simple wolframite‐type phase.