A new route to potassium and ammonium pentaborate dihydrates, A[B5O6(OH)4]·2H2O (A = K or NH4), and synthesis and structural assessment of new fluoro(hydroxo)oxoborate dihydrates, A2[B2O2F2(OH)2]·2H2O (A = K or NH4)

Abstract

Potassium and ammonium pentaborate dihydrate, A[B5O6(OH)4]·2H2O (A = K or NH4), and fluoro(hydroxo)oxoborate dihydrates, A2[B2O2F2(OH)2]·2H2O (A = K or NH4), have been synthesised, respectively, from the reaction of a suspension of boric acid in water with potassium hydroxide or aqueous ammonia at pH 9 followed by the addition of acetylacetone, and from the reaction of a solution of boric acid and the corresponding AF (A = K or NH4) in 48% HF at steam-bath temperature. Their characterisation and structural assessment are based on the results of elemental analyses and conductance measurements, i.r. and laser-Raman spectroscopic studies.