Barium pyroborate can be prepared by the reaction of
the oxides at high temperature:
2BaO + B2O3 + heat→Ba2B2O5
Crystals can be grown from a mixture containing
appropriate amounts of BaCO3 and H3BO3, using KFB4
as a flux. The mixture is thoroughly milled, heated in
a platinum crucible in air to 1193 K (920 °C), and kept
at that temperature for 15 h. The temperature is then
quickly quenched to 1053 K (880 °C) and slowly cooled
from 1053 to 973 K (700 °C) at a rate of 0.011 K/h and
then air quenched to room temperature. Colorless crystals
are obtained.
