Normal coordinate analysis of α-FeOOH - a molecular approach

Verdonck, L.; Hoste, Serge; Roelandt, F.F.; Kelen, G.P. Van Der

doi:10.1016/0022-2860(82)85065-5

Cited by 92 publications

(37 citation statements)

References 7 publications

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“…1, top spectrum) exhibits a broad band in the 2600-3800 cm À1 region, two sharper bands of lower intensity in the 1600-1800 cm À1 region and two other bands in the 700-900 cm À1 region. These features are consistent with previously published values for synthetic goethite (Schwarzmann and Sparr, 1969;Parfitt et al, 1975;Rochester and Topham, 1979a,b;Busca et al, 1978;Verdonck et al, 1982;Morterra et al, 1984;Ishikawa et al, 1986;Williams and Guenther, 1996;Weckler and Lutz, 1998;Ruan et al, 2001Ruan et al, , 2002Krehula et al, 2002;Subbanna et al, 2002;Betancur et al, 2004). All bands undergo substantial changes with temperature, as it will be discussed further in Section 3.2.…”

Section: Ftir Spectra Of Goethitesupporting

confidence: 89%

A combined FTIR and TPD study on the bulk and surface dehydroxylation and decarbonation of synthetic goethite

Boily

Szanyi

Felmy

2006

Geochimica et Cosmochimica Acta

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Section: Ftir Spectra Of Goethitesupporting

confidence: 89%

A combined FTIR and TPD study on the bulk and surface dehydroxylation and decarbonation of synthetic goethite

Boily

Szanyi

Felmy

2006

Geochimica et Cosmochimica Acta

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“…All samples contain the characteristic OH stretching (OH) and HOH bending (␦OH) vibrational bands at 3423-3444 cm −1 and 1641.1 cm −1 , respectively [24][25][26]. These bands were reported in pure iron oxides [27,28]. The broad absorption band around 3423.4 cm −1 (Fig.…”

Section: Fourier Transform Infrared (Ftir) Spectroscopymentioning

confidence: 93%

XPS and FTIR spectroscopic study on microwave treated high phosphorus iron ore

Omran

Fabritius

Elmahdy

et al. 2015

Applied Surface Science

133

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a b s t r a c tA growing interest in microwave heating has emerged recently. Several potential microwave applications regarding minerals' processing have been investigated. This paper investigates the effect of microwave radiation on Egyptian high phosphorus iron ore. Three different iron ore samples have varying Fe 2 O 3 and P 2 O 5 contents and mineralogical textures were studied. A comparative study has been carried out between untreated and microwave treated iron ore. XRD and FTIR analyses showed that after microwave radiation the crystallinity of iron bearing minerals (hematite) increased, while the functional chemical groups of phosphorus bearing minerals (fluorapatite) and other gangues dissociated. High resolution XPS analyses of Fe 2p peaks showed that after microwave radiation a portion of Fe(+III) was reduced to Fe(+II). This means that after microwave radiation iron oxide (hematite, Fe 3+ ) transformed into more magnetic phase. The results indicated that microwave radiation had a positive effect on the magnetic properties of iron oxide, through formation of ferromagnetic phases.

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“…Those results can still be related to particle shape and size effects. This band occurs at the highest Fe-O stretching frequency, and the stretching seems to be along the shortest Fe-O bond (Verdonck et al, 1982). Does it reflect an increase of this bond length (and a decrease of the bond strength) when the H-bond is stronger, a lower and the octahedra more tilted?…”

Section: General Interpretationmentioning

confidence: 99%

“…It seems unlikely (Fig. 4) and it should be considered rather that this frequency does not correspond to a pure stretching mode along this single bond (where Verdonck et al (1982) found 66% of the energy of the vibration).…”

Section: General Interpretationmentioning

confidence: 99%

Infrared study of goethites of varying crystallinity and particle size: II. Crystallographic and morphological changes in series of synthetic goethites

Cambier

1986

Clay miner.

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Low crystallinity of unsubstituted goethites is characterized by a small coherently diffracting domain, which may be accompanied by another type of disorder revealed by broader IR half-absorbance band widths. Inside the unit cell, the H-bond is weaker, which increases the OH stretching frequency and lowers the bending frequencies. Also, an increase in parameter a and a change in Fe--O bonds, which might correspond to a minor tilting of octahedra, occur along with a lowering of the frequency of the 630 cm -1 band.In the previous paper of this series (Cambier, 1986), the problem of the relationship between crystallinity and IR properties of goethites was examined. The typical IR spectrum of goethites was discussed in an attempt to isolate which factors can influence the frequencies of major bands. For the OH bands, the effect of coupling between' the four OH in the unit cell was defined. For two lattice bands, the attribution of Verdonck et al. (1982) was discussed and the orientation of transition moments determined.It is now possible to specify how the IR spectra define the crystallinity of pure unsubstituted goethites, a series of which was prepared (Schwertmann et al., 1985). In an attempt to separate effects due to 'poor crystallinity' (interpreted as disorder) from effects due to particle size, a second series with varying crystallinity and constant particle size was added. A wide range of physico-chemical properties was considered previously (Schwertmann et al., 1985) whereas the purpose of the present paper is to demonstrate how IR absorption parameters clarify some aspects of the crystaUinity of goethites. MATERIAL AND METHODS SamplesTwo series of goethites were prepared. For the first, series 39/T, 50 ml of 1 M Fe(NO3) 3 solution were added to 450 ml of KOH kept at T~ to yield a final OH concentration of 0.70 ~l. The suspensions were stored at T for various periods of time (Table 1) until the oxalate-soluble iron fraction (Schwertmann, 1964) was <2%, indicating essentially complete crystallization. All the samples were pure goethites except that stored at 80~ which contained traces of hematite. This series showed better crystallinity and increasing 1986 The Mineralogical Society

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Normal coordinate analysis of α-FeOOH - a molecular approach

Cited by 92 publications

References 7 publications

A combined FTIR and TPD study on the bulk and surface dehydroxylation and decarbonation of synthetic goethite

A combined FTIR and TPD study on the bulk and surface dehydroxylation and decarbonation of synthetic goethite

XPS and FTIR spectroscopic study on microwave treated high phosphorus iron ore

Infrared study of goethites of varying crystallinity and particle size: II. Crystallographic and morphological changes in series of synthetic goethites

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