Ab initio calculation of 1H, 17O, 27Al and 29Si NMR parameters, vibrational frequencies and bonding energetics in hydrous silica and Na-aluminosilicate glasses

Water speciation in hydrous silicate and aluminosilicate glasses: Direct evidence from 29Si-1H and 27Al-1H double-resonance NMR

“…The predicted sequence of 1 H chemical shift ranges [Si(OH)Al > SiOH > (Ca,Mg)OH and AlOH] also conforms with that expected from their relative acidity/bacisity property (Xue andKanzaki 2004, 2007). However, different views also exist (e.g., Kubicki and Sykes 2004), because non-hydrogen-bonded (isolated) SiOH and Si(OH)Al species, such as those found on the surface of minerals/gels, or in isolated model clusters from ab initio calculations, can give lower 1 H chemical shifts than those of the corresponding hydrogen-bonded species.…”

Bond-valence methods for pKa prediction. II. Bond-valence, electrostatic, molecular geometry, and solvation effects

“…We speculated that perhaps the -OH and -OH 2 groups in hexaquo cations are easily interchangeable, leading to an averaging effect. Or it may simply be a product of how the H-bonding environment of these O atoms changes with deprotonation (Kubicki and Sykes, 2004). Whatever the explanation, there is evidence that such a difference in treatment of hexaquo cations and oxyacids should be necessary.…”

Hydrogen–sodium interdiffusion in borosilicate glasses investigated from first principles

“…The breaking of the B IV -O-T bonds that follows the substitution of Na + by H 3 O + indicates that the proton is unable to counterbalance the charge of the BO 4 tetrahedra in a borosilicate glass, which is probably a major difference between hydrated borosilicate and aluminosilicate glasses, in which the presence of bridging hydroxyls has been proved on Al-O-Si bonds (with four-fold coordinated Al atoms) within RMN experiments [19][20][21] and ab initio calculations [22,23].…”