Raman, IR, and ²⁷Al-MAS-NMR Spectroscopic Studies of Sodium (Hydroxy)Aluminates

Abstract

A series of solid sodium (hydroxy)aluminates has been prepared from highly caustic aqueous sodium aluminate solutions. The coordination geometry of the aluminum in these compounds was established by 27Al magic angle spinning nuclear magnetic resonance (27Al-MAS-NMR) spectroscopy and was used to identify the Raman and IR vibration frequencies characteristic of tetrahedral (Raman: 440 cm−1; IR: 823 cm−1 and 540 cm−1) and octahedral (Raman: 490–500 cm−1; IR: 728 cm−1) aluminum sites. The vibrational spectra of these solids differ markedly from those observed for concentrated aqueous solutions, and it appears that solid-state vibrational spectra cannot be used to predict the structure of aluminate species existing in solutions.

Microstructural Properties of High Level Waste Concentrates and Gels with raman and Infrared Spectroscopies

“…For totally symmetric vibrations, the depolarization ratio has a value close to zero. Assignment of the 620 cm-' band to the totally symmetric Al-O vibration of the monomeric Al(OH)d-species is confmed by the very small depolarization value of 0.0 1 in agreement with recently reported values (15). The larger depolarization ratios of 0.04 and 0.17 for the 53 7 and 692 cm-' bands indicate that these vibrational modes have lower symmetry.…”

“…The phase boundaries for these solid phases are based on published solubility studies. These solid aluminate phases have been identified in structural and in spectroscopic studies of precipitates associated with concentrated sodium ahuninate solutions (15).…”

Laser ablation in analytical chemistry—a review

“…Certain plants from a specific area or geological environment characterize uniquely the source of the plant. Walting [154] showed trace element 'fingerprint' patterns of cannabis crops and the association of these crops to specific geological environments.…”

Synthesis and spectroscopic study of mesoporous aluminum methylphosphonate foam templated by dibutyl methylphosphonate

“…3(d), the mesopores in the walls have an average diameter of 8 nm. Table 1 shows the assignments of the characteristic absorption bands of DMM, AMP and AMPF [33,38,[41][42][43][44]. Some special assignments are discussed as follows.…”