Boronate-linked materials types

Boron is a metalloid that occurs in nature mainly as borate minerals, such as borax, Na2B405(0H)4-8 H2O, and borosilicates. In biological material, compounds of boron (boric acid and borates) form stable complexes with polyhydroxy compounds, such as sugar alcohols, sugars and substances derived from them (nucleotides, riboflavin and ascorbic acid). An example is the binding of boric acid, B(0H)3 or more accurately of borate ions, to the ds-hydroxyls (at positions C-2 and C-3) oftwo P-o-apiose residues (6-39) located in different chains of a structural type of pectin called rhamno-galacturonan II, which are cross-linked in this way (see Section 4.5.6.6.1). 

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