Phase equilibria in the system SrO--CdO--V2O5

Phase equilibria in the system SrO‐CdO‐V 2 O 5 in air were established from data obtained by DTA, quenching, and high‐temperature solid‐state reaction experiments. The SrO‐V 2 O 5 boundary system contains 4 compounds at SrO to V 2 O 5 molar ratios of 4:1, 3:1, 2:1, and 1:1. A fifth compound with a molar composition of ∼10:3 with the apatite crystal structure was also found; it may, however, be a hydroxyapatite phase. The CdO‐V 2 O 5 system contains the compounds 3CdO·V 2 O 5 , 2CdO·V 2 O 5 , and CdO·V 2 O 5 . The latter compound exhibits a rapid reversible polymorphic transition at 180°C. Complete solid solubility exists in the SrO‐CdO system. The most probable compatibility relations were determined from the data available for the SrO‐CdO‐V 2 O 5 ternary system. Limited solid solubility exists between SrO·V 2 O 5 and CdO·V 2 O 5 , and the high‐temperature CdO·V 2 O 5 polymorph is stabilized to room temperature by solid solution of SrO·V 2 O 5 . Evidence for the existence of 2 ternary compounds with limited local solid solubility is also presented.