CHAPTER 12 - Boron

Abstract

Publisher Summary Distillation as methyl borate is regarded as the classical procedure for the separation of boron, but conflicting reports exist in the literature regarding the adequacy of this method. This chapter describes the spectrophotometric determination of boron in silicate rocks. Of the many reagents described for the photometric determination of boron, only curcumin, dianthrimide (1,1′-iminodianthraquinone) and carmine (carminic acid) are used extensively. The chapter discusses the titrimetric determination of boron in tourmaline. One of the earliest procedures to be devised for the determination of boron in silicate rocks and minerals was that of titrating liberated boric acid with standard alkali in the presence of a polyhydric alcohol—mannitol being now commonly employed. The boric acid–mannitol complex acts as a strong monobasic acid. When combined with an ion-exchange separation, this procedure can be simply and easily applied to the analysis of tourmaline and other silicate minerals containing boron as a major component.