Vibrational spectra of augelites Al2(OH)3(XO4) (X=P, As, V)

Raman and infrared spectroscopic characterization of the phosphate mineral paravauxite Fe2+Al2(PO4)2(OH)2⋅8H2O

“…In the Raman spectrum of paravauxite in the RRUFF data base, Raman bands are observed at 133, 211, 232 and 283 cm À1 . Breitinger et al [29] reported low intensity bands for synthetic augelite at 750 and 530 cm À1 which were assigned to the m(Al(O/OH) n ) modes. The Raman spectrum displays a Fig.…”

On the destruction of kaolinite and gibbsite by phenylphosphonic, phenylphosphinic and phenylarsonic acids: evidence for the formation of new Al compounds

“…In comparison to the original five intense bands of gibbsite, only a small band was observed at 3525 cm À1 . Other bands were characteristic of the aromatic ring with attached P (between 3000 and 3100 cm À1 and at 1594, 1486 and 1435 cm À1 ) and the PÀO stretching bands between 1000 and 1300 cm À1 (Thomas & Chittenden, 1970;Cabeza et al, 1998;Haky et al, 1997;Morizzi et al, 2000;Breitinger et al, 2001). One notes the strong decrease in intensity of many lower-frequency bands attributed to hydroxyl bending and deformation modes, especially the gibbsite bands at 1018, 966 and 666 cm À1 (Frost et al, 1999;Wang & Johnston, 2000;Ruan et al, 2001;Kloprogge et al, 2002).…”

“…The spectrum of dried K-PPA showed the four hydroxyl stretching bands of the raw kaolinite (3693, 3668, 3653 and 3619 cm À1 ) in very small intensities (Olejnik et al, 1968;Frost, 1995;Frost et al, 1997;Balan et al, 2001;Bougeard et al 2000); bands characterizing the P-C 6 H 5 bond and the phenyl ring (1436, 1487, 1594 cm À1 , four bands in the 3000À3100 cm À1 region); and very intense PÀO stretching bands between 1000 and 1300 cm À1 (Thomas & Chittenden, 1970;Cabeza et al, 1998;Haky et al, 1997;Morizzi et al, 2000;Breitinger et al, 2001). The SiÀO stretching bands (1114, 1102, 1030 and 1009 cm À1 ) and the SiÀOÀAl/OÀSiÀO bending bands (538, 470 and 431 cm À1 ) (Olejnik et al, 1968;Frost, 1995;Frost et al, 1997;Balan et al, 2001;Bougeard et al, 2000) were largely reduced in intensity or absent.…”

“…The FTIR spectrum of K-PPiA showed many similarities with that of K-PPA. The major bands were: the four OH-stretching bands, again with much reduced intensity; bands of the P-C 6 H 5 bond and the phenyl ring (1438, 1483, 1594 cm À1 , three bands at 3000À3100 cm À1 ); an intense P-H stretching band at 2380 cm À1 ; and the very intense PÀO stretching bands between 1000 and 1300 cm À1 (Nakamoto, 1986;Morizzi et al, 2000;Breitinger et al, 2001). The interpretation of the spectrum in the region below 1200 cm À1 was even PPiA (e) between 1800 and 400 cm À1 .…”

“…In the hydroxylstretching region, only a broad band with two maxima at 3526 and 3439 cm À1 was seen instead of well defined bands. The bands related to the aromatic ring with attached phosphorus were also present (3000À3100 cm À1 , 1594, 1487 and 1436 cm À1 ), as well as a band of medium intensity in the 2380 cm À1 region, attributed to the PÀH stretching mode (Nakamoto, 1986;Morizzi et al, 2000;Breitinger et al, 2001). The characteristic PÀO stretching bands at the 1000À1300 cm À1 region and the strong intensity decrease of most hydroxyl bending and deformation bands in the lower-frequency region (especially those at 1018, 795 and 666 cm À1 in the gibbsite spectrum) were also typical of this spectrum.…”