Combined vibrational spectra of natural wardite

Authors :: János Mink
Stewart F. Parker
H.-H. Belz
R. G. Schwab
Viktória Komlósi
G. Brehm
László Hajba
Dietrich K. Breitinger
D. Colognesi
Source :: Journal of molecular structure, 706 (2004): 95–99. doi:10.1016/j.molstruc.2004.01.039, info:cnr-pdr/source/autori:Breitinger D. K. (a); Belz H.-H. (b); Hajba L. (c); Komlósi V. (c); Mink J. (c); Brehm G. (d); Colognesi D. (e)*; Parker S. F. (e); Schwab R. G. (f)/titolo:Combined vibrational spectra of natural wardite/doi:10.1016%2Fj.molstruc.2004.01.039/rivista:Journal of molecular structure (Print)/anno:2004/pagina_da:95/pagina_a:99/intervallo_pagine:95–99/volume:706
Publication Year :: 2004
Publisher :: Elsevier BV, 2004.
Abstract: Vibrational spectra (IR, Raman, inelastic neutron scattering) were measured of natural wardite (ideal formula NaAl 3 (OH) 4 (PO 4 ) 2 ·2 H 2 O) from Trauira, Brazil, with the main impurities Fe and Ca. The spectra are discussed on the basis of a symmetry analysis restricted to one layer in the four-layer structure. The band pattern in the ν (OH) region is due to two different Al 2 OH groups and their correlation coupling; their deformations δ and γ are assigned based on IR and INS spectra. Contributions of the hydrogen-bonded H 2 O molecules are discussed, as are the vibrations of the AlO 6 octahedra dominating the Raman spectrum. From the fundamentals ν (OH) of the OH groups and their overtones anharmonicity constants have been estimated.