Solid-state NMR investigation of phosphorus in aluminoborosilicate glasses

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

“…The two resonances were assigned to Q 1 and Q 2 phosphate sites, respectively, and there is no evidence of Q 0 or Q 3 sites from the spectra. The data are consistent with the accepted binary depolymerization model [39,42,53], and also consistent with previous studies. The Q 2 species may be a part of linear chain or ring structures or a combination of both, and different ring structures may have a distribution of P-O-P angles and P-O bond lengths resulting in the larger line widths usually observed for Q 2 species.…”

“…More detailed structural information is obtained by employing double resonance NMR techniques. The REDOR [43] and TRAPDOR [39,53] methods report on proximities between heteroatoms by reintroducing nuclear spin dipolar interactions under magic-angle spinning conditions [34,48]. Here we utilize TRAPDOR as it provides larger dephasing of the echo signals by involving all of the nuclear Zeeman energy levels of the quadrupolar nuclei [48], compared to RE-DOR, which involves only the central (m = 1/2 to m = À1/2) transition.…”

“…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].…”

“…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].…”

Phosphate speciation in sodium borosilicate glasses studied by nuclear magnetic resonance

“…Rong et al studied the speciation of phosphorus in aluminoborosilicate glasses by NMR [22]. In all of the compositions studied, they found resonances at 16 and 3.4 ppm, assigned to mono-and diphosphate species, respectively.…”