Oxygen environment of rare-earth ions in phosphates with. beta. -K/sub 2/SO/sub 4/ type structure

The use of europium as a local structure probe allowed the authors to determine the various phases appearing at room temperature in the NaPO/sub 4/-Na/sub 3/Eu(PO/sub 4/)/sub 2/ and NaSrPO/sub 4/-Na/sub 3/Eu(PO/sub 4/)/sub 2/ systems. The broadening of the europium emission lines in going from the calcium to the strontium phases illustrates the ease of movement of the (PO/sub 4/) groups.