Boric Oxide, Boric Acid, and Borates

Abstract

Often referred to as borates, boron oxide compounds find extensive industrial use. These compounds, in which boron is bonded exclusively to oxygen, are produced on a vastly larger scale than all other classes of boron compounds combined. Global consumption of borates in 2014 was estimated at 2.0 × 10 6 t of B 2 O 3 equivalent. Borates are used for the manufacture of many products, such as flat‐screen displays, kitchenware, ceramic glazes and enamels, industrial fluids, high‐strength alloys, personal care and cleaning products, fiberglass insulation, and building materials. Borates are also vital agricultural micronutrients. Important borate mineral resources are the sodium borates kernite and tincal (borax), the calcium borate colemanite, and the sodium calcium borate ulexite, which together account for ca. 90% of industrial borate production. More than 70% of borate production is based in Turkey and the USA, and the remainder primarily in South America and East Asia. Chemical and physical properties of the more important refined and mineral borates are described. The more significant industrial applications of borates are described, and toxicological aspects of borates are reviewed. The article contains sections titled: 1. Introduction 2. Resources 3. Nomenclature 4. Boric Oxide 4.1. Physical Properties 4.2. Chemical Properties 4.3. Production 5. Boric Acid 5.1. Physical Properties 5.2. Chemical Properties 5.3. Production 6. Aqueous Borate Solutions 7. Sodium Borates 7.1. Sodium Tetraborates 7.2. Sodium Metaborate Hydrates 7.3. Sodium Pentaborate 7.4. Disodium Octaborate Tetrahydrate 7.5. Sodium Peroxoborates 8. Calcium and Sodium Calcium Borates 9. Lithium Borates 10. Potassium Borates 11. Ammonium Borates 12. Zinc Borates 13. Borate Glasses 14. Quality Specifications 15. Analysis 16. Uses 16.1. Glasses and Ceramics 16.2. Industrial Fluids 16.3. Adhesives 16.4. Oil and Gas Recovery 16.5. Water Treatment 16.6. Agriculture 16.7. Biocides 16.8. Cleaning and Personal‐Care Products. 16.9. Fire Retardants 16.10. Metallurgy 16.11. Gypsum Wallboard 16.12. Nuclear Technology 16.13. Pulp and Paper 17. Economic Aspects 18. Toxicology and Occupational Health

Pentaborate(1-) Salts and a Tetraborate(2-) Salt Derived from C2- or C3-Linked Bis(alkylammonium) Dications: Synthesis, Characterization, and Structural (XRD) Studies

“…Measured porosities of the thermally treated samples were in the range 0.06-0.94 m 2 /g indicating that they were all essentially non-porous and in accord with previous work [31,32]. 1 H-, 13 C-and 11 B-NMR spectra were recorded on compounds 1-9 (D 2 O solvent) and 1 H-and 13 C-spectra were in accord with the cations present. Exchangeable NH and B-OH protons were absent as specific signals and it is assumed were observed in the HOD signal present at +4.79 ppm as has been observed previously in related non-metal cation systems [31][32][33].…”

“…These compounds are structurally diverse, with the polyborate anions generally comprised of trigonal planar 3-coordinate and tetrahedral 4-coordinate boron centres, linked via oxygen bridges with as many terminal OH or O − groups as is necessary to complete the required geometry at boron [6][7][8][9][10][11]. Some polyborate salts are sold as bulk chemicals for use in the glass/vitreous, fire retardant, and agricultural industries [12][13][14], whilst other synthetic polyborates have interesting and specialized physical e.g., semiconducting, luminescent, non-linear optical (NLO) properties [5,15]. We are interested in synthetic polyborate chemistry and recently have started to investigate non-metal cation stabilized silicate/borate solutions as potential…”

Oxidoborates Templated by Cationic Nickel(II) Complexes and Self-Assembled from B(OH)3

“…A drawing of the structure of trans-[Ni(en)(H2O)2{B6O7(OH)6}] . H2O (7), with selected crystallographic numbering, can be found in Figure 3. Compound 7 is a distorted neutral octahedral Ni (II) The dach ligands are also disordered in 6 but have chair conformations with their amino groups equatorial and with one dach ligand in each cation having R,R stereochemistry and the other S,S.…”

“…Crystallographic data for 1-8 are given in the experimental section. The crystallographic data collection of compounds were performed on a Rigaku FR-E+ diffractometer (1, 3-8) equipped with an AFC12 goniometer, an HG Saturn 724+ detector and either HF varimax confocal mirrors (1,3,4,(6)(7)(8) or VHF varimax confocal mirrors (5). Data for 2 were obtained on DLS synchronous beamtime 119 equipped with a crystallographic goniometer and a Rigaku HG Saturn 724 detector.…”

“…Synthetic borates (oxidoborates is the IUPAC recommended name for this class of compounds [1]) show great structural diversity and their structures complement the variety of structural motifs observed in borate minerals [2][3][4][5]. Borate minerals have large scale economic importance [6][7][8] (e.g., as vitreous, agriculture, fire retardant products) and some of these minerals, and their synthetic counterparts, have also found more specialist uses [9][10][11][12][13][14][15][16][17][18] (e.g., as fluorescent, optical SHG and wide band-gap semi-conductor materials).…”