The thermal decomposition o
f guanidinium tetraborate, pentaborate, and nonaborate has beencharacterized under nitrogen and ammonia atmospheres, and conditions have been de
fined
for bulk powderand aqueous aerosol trans
formations o
f these precursors to boron nitride (BN). The bulk pyrolyses underammonia (600-1400
![](/images/entities/deg.gi<font color=)
f">C) produce micrometer- and sub-micrometer-sized platelet morphology particleswith oxygen contents o
f 3-18 wt. %. Subsequent pyrolysis o
f these powders at 1600
![](/images/entities/deg.gi<font color=)
f">C under NH
3reduces the oxygen contents to <1 wt. %. Pyrolysis o
f aqueous aerosols containing the guanidiniumborates gives submicrometer spherical morphology BN particles. The chemistry and processing o
fguanidinium borates are compared with the behavior o
f alternative precursors.