Oxide compound formation between boron and excess magnesium

Amitabha Mitra, Burl C. Yearwood, Timothy S. Keizer, David A. Atwood

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Mixtures of boric anhydride (B2O3) or orthoboric acid (B(OH)3) with MgO in 1:1, 1:10 and 1:100 ratios were heated in alumina crucibles from 400°C to 1000°C. The resulting crystalline compounds were identified by powder X-ray diffraction. Solid state 11B NMR and FT-IR were used to identify the boron bonding environment. Three- and four-coordinate boron species were found in the mixtures at the various temperatures. Temperature had the greatest effect on which compounds could be identified, with no effect observed below 800°C. It was found that mixtures of boron oxide and magnesium oxide produced a magnesium hexaborate (MgB6O10·7H2O) and suanite (Mg2B2O5), whereas mixtures of boric acid and magnesium oxide produced kotoite (Mg3(BO3)2) and suanite. Thus, the type of boron starting material in the solid mixture determined what compounds formed at higher temperatures. The implication is that, at low levels, the boron reagents combine with magnesium oxide differently during heating and with boric acid, before dehydration occurs.

Original languageEnglish
Pages (from-to)193-201
Number of pages9
JournalMain Group Chemistry
Volume9
Issue number1-2
DOIs
StatePublished - 2010

Keywords

  • Magnesium oxide
  • X-ray powder diffraction
  • boric acid
  • boron oxide
  • infrared spectroscopy
  • mineral formation
  • solid-state NMR

ASJC Scopus subject areas

  • Organic Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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