Phase equilibria in the K2O-MgO-B2O3 system

Subsolidus (500–700°C) phase relations in the K 2 O-MgO-B 2 O 3 system have been studied by X-ray diffraction. The results are used to construct the phase compatibility diagram of the K 2 O-MgO-B 2 O 3 system in the range 650–700°C. A new ternary compound of composition K 2 Mg 3 B 2 O 7 , with the constituent oxides in the molar ratio 1: 3: 1, is identified.