Vibrational spectra of synthetic crandallite‐type minerals—optical and inelastic neutron scattering spectra

Abstract

The consequences of the resulting perturbed symmetry and of the non-equivalence of the bridging m-OH groups in the Al 2 OH fragments were pointed out (complexity of the n(Al 2 O-H), d(Al 2 OH) and g(Al 2 OH) bands). The vibrations of the PO 4 and HPO 4 groups could be separated. Some aspects of the vibrational behaviour of the AlO 2 (OH) 4 units and of the layers composed therewith were addressed. The translational modes of the interlayer cations Ca 2+ and Sr 2+ could be observed; the findings support the suggested displacement of Ca in crandallite.

Composition of characteristic soils on the raised atoll Bellona, Solomon Islands

“…However, apatite and crandallite structures readily accept substitution of both cations and anions, and we interpret the observed correlation as evidence of the existence of a specific carbonate type of crandallite with carbonate for phosphate substitution. All absorption bands in the spectra of the crandellite-dominated samples investigated here are slightly shifted compared to those reported for pure synthetic crandallite by Breitinger et al (2006). Some diffraction peaks due to crandallite exhibit a distinct broadening at the bases and asymmetry towards low angle (e.g.…”

“…4). The split ν 3 carbonate bands are absent in the spectrum of synthetic crandallite (Breitinger et al, 2006). However, apatite and crandallite structures readily accept substitution of both cations and anions, and we interpret the observed correlation as evidence of the existence of a specific carbonate type of crandallite with carbonate for phosphate substitution.…”

“…4B and D). Crandallite, which was structurally characterized by Blount (1974) and Breitinger et al (2006), was tentatively identified in Bellonese phosphatic clay half a century ago (Warin, 1961) and has been reported to occur in other phosphate-rich sediments (Francisco et al, 2007;Garrett et al, 2010;Whitehead et al, 1993). Both diffractograms show additional peaks at 0.416 nm, assigned to goethite (α-FeOOH) (see further below) and at 0.485 and 0.616 nm that are tentatively assigned to gibbsite (Al(OH) 3 ) and boehmite (γ-AlOOH), respectively.…”

Pre-historic production of ceramics in the Amazon: Provenience, raw materials, and firing temperatures

“…4b) and the total chemical analyses (Table 2), resulted in the identification of these minerals in the ceramic sherds from Da Mata, albeit in much smaller quantities. These phosphates can be recognized by the anti-symmetric stretching of the P-O, 1035 cm − 1 (Breitinger et al, 2006) found in the ceramic sherds from all the sites, and equivalent to variscite. Segelerite (CaMgFe(PO 4 ) 2 (OH)·4(H 2 O)) was also identified by XRD in the sherds from Monte Dourado 1 (Fig.…”

Raman spectroscopy at the beginning of the twenty‐first century

“…Breitinger et al 25 studied the synthetic minerals crandallite and goyazite by IR, Raman, and inelastic neutron scattering. Therein the authors have investigated the influence of disorder.…”