The dissolution of CsXeF7in molten alkali fluoroberyllate glasses between 250° and 500°C is described. The apparent small solubility of Xe(VI) in these ionic glass‐forming melts (about 1 to 2 wt% or less) may be related to retention of a molecular configuration by XeF6that is caused by its strong fluoride ion donor properties and/or to the nonmelting behavior of numerous MF‐XeF6salts when they are heated. Rather low‐softening (about 100°C) glasses were also prepared in the TIHF2‐NaHF2‐BeF2system, whereas TlHF2has a relatively low melting point (about 85°C). Contrary to expectations, Xe(VI) appears to oxidize TI+in these molten glass environm