TRAPDOR NMR investigations of phosphorus-bearing aluminosilicate glasses

Saturation des minéraux phosphatés dans les magmas silicatés :

“…For example, the existence of P-Fe 3+ complexes has been held responsible for the fact that small additions of P2O5 dramatically influence the stability field of magnetite (Toplis et al, 1994a). This is also consistent with the general finding that P 5+ is associated with trivalent cations in silicate liquids, for example, rare earth elements (Ryerson and Hess, 1978), and Al 3+ (Toplis and Schaller, 1998;Schaller et al, 1999).…”

Predicting phosphate saturation in silicate magmas: An experimental study of the effects of melt composition and temperature

“…For example, the existence of P-Fe 3+ complexes has been held responsible for the fact that small additions of P 2 O 5 dramatically influence the stability field of magnetite (Toplis et al, 1994a). This is also consistent with the general finding that P 5+ is associated with trivalent cations in silicate liquids, for example, rare earth elements (Ryerson and Hess, 1978), and Al 3+ (Toplis and Schaller, 1998;Schaller et al, 1999).…”

Solid-state NMR investigations of sodium–cesium mixed-alkali phosphate glasses

“…More complex solid-state NMR experiments such as dynamic angle spinning (DAS) NMR [36,37] and multiple-quantum MAS techniques [38] average second-order quadrupolar interactions, and are often needed to resolve distinct structural environments from quadrupolar nuclei. Utilizing another new class of solid-state NMR methods, dipolar connectivity results have been reported recently from phosphorus containing glass systems [39][40][41][42], and a double resonance experiment based on DAS and cross-polarization has been carried out to demonstrate the connectivity between distinct phosphorus and sodium sites in mixed alkali phosphates [16]. In those connectivity experiments the dipolar interactions between 31 P and modifying cations are exploited to probe structural correlations that exist between these nuclei.…”

“…It has been well established that dipolar recoupling techniques such as rotational echo double resonance (RE-DOR) [43,44], transferred echo double resonance (TEDOR) [44], and radiofrequency dipolar recoupling (RFDR) [45], provide useful internuclear distance information for spin-1/2 nuclei, while transfer of populations via double resonance (TRAPDOR) NMR has proven to be an ideal technique for studying dipolar interactions between spin-1/2 and quadrupolar nuclei [46][47][48]. TRAPDOR NMR has been effectively utilized as a probe of local structure in a wide variety of materials including zeolites [48,49] aluminophosphates [42], aluminates [50], vanadates [51], polymers [52], and oxide glasses [39,42,53]. TRAPDOR experiments involving phosphorus and sodium (or aluminum) have been utilized to assign the distinct phosphorus sites in commercial or radioactive waste glasses [39,53] and a series of aluminophosphate glasses [42].…”