A Mössbauer and I.R. Spectroscopic Study of the Structure of Nontronite

Goodman, B. A.; Russell, J. D.; Fraser, A. R.; Woodhams, F. W. D.

doi:10.1346/ccmn.1976.0240201

Cited by 216 publications

(202 citation statements)

References 27 publications

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“…An intense Si-O stretching absorption was noted at 1005 cm -1 (Figure 6b), in complete agreement with the results of Goodman et aL (1976), who correlated the position of this band in nontronites with the amount of Fe 3 § in tetrahedral sites. The percentage of total iron occupying tetrahedral positions in sample KL9 is 17% by chemical analysis and 18% by M6ssbauer spectroscopy.…”

Section: Infrared Spectrasupporting

confidence: 90%

“…These parameters closely resemble those reported for nontronites by Goodman et aL (1976), indicating that the relatively high concentration of Mg in this sample does not significantly affect the configuration of the octahedral sheets.…”

Section: Electron Microscopysupporting

confidence: 86%

“…Similar considerations apply to the OH-bending vibrations ( Figure 6b). Following Goodman et al (1976), the absorption at 818 cm-~ may be assigned to Fe-OH-Fe and the inflection at about 790 cm -~ to FE-OH-Mg vibrations. If these assignments are correct, the intensity of this absorption supports the suggestion that the incidence of Mg-OH-Mg groups is greater than would be expected from a random distribution of octahedral cations.…”

Section: Oh-stretching and -Bending Absorptionsmentioning

confidence: 99%

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Nontronite in a Deep-Sea Core from the South Pacific

Singer

Stoffers

Heller-Kallai

et al. 1984

Clays and clay miner.

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Abstract--Smectite close to the pure Fe end member of the nontronite-beidellite series was found in the fine clay separated from a 354-cm deep sediment core in the southwestern Pacific Basin. The mineral has a b-axis of 9.09/~ and an unusually low dehydroxylation temperature of 454~ and is composed of sheaves of fibers less than 50/~ wide. Its charge density is 5.09 x 10 -4 esu/cmL The charge originates mainly from the presence of 18% of the total Fe in tetrahedral positions, as determined by Mrssbauer analysis. Slight deviations of the infrared spectra from those reported for nontronites are probably due to the presence of more octahedral Mg. The presence of authigenic quartz in the same sample permits some speculation on the concentration of dissolved silicon during nontronite genesis. A 6~80 value of 26 + 0.3%o indicates a temperature of formation of about 22~ The Sr isotope ratio suggests that the nontronite formed at least 12 million years ago.

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Section: Infrared Spectrasupporting

confidence: 90%

Section: Electron Microscopysupporting

confidence: 86%

Section: Oh-stretching and -Bending Absorptionsmentioning

confidence: 99%

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Nontronite in a Deep-Sea Core from the South Pacific

Singer

Stoffers

Heller-Kallai

et al. 1984

Clays and clay miner.

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“…Applying Eq. (1) to sample SWa-1, assuming an oxidized structural formula (Goodman et al, 1976) of Nao.32s(Si3.65A1o.35)(A10.53Fe(III)~.366Mgo.~3)Olo(OH)2, (2) [compensating cation stoichiometry added based on Stucki (1988)] and a reduced structural formula of Nao.577(Si3.65A10.35)(Alo.53Fe(III)o.6s3Fe(II)o.683 9 Mgo. 13)Olo(OI-1)2,…”

Section: Stacking Order In the A-b Planementioning

confidence: 99%

Effects of Iron Oxidation State on the Texture and Structural Order of Na-Nontronite Gels

Stucki

1991

Clays and clay miner.

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--Aqueous gels of unaltered (oxidized) and chemically reduced ferrnginous smectite (SWa-1 from the Source Clays Repository of The Clay Minerals Society) were characterized by transmission electron microscopy, electron diffraction, and energy-dispersive X-ray fluorescence to establish details regarding their texture, inter-layer and inter-particle arrangements, and chemical composition. Micrographs revealed that the reduction of structural Fe(III) to Fe(II) caused a consolidation of smectite particles from an extensive network of smaU crystals (1-6 layers thick) to distinct particles of limited size in the a-b direction and about 20-40 layers thick. The interlayer distances in the reduced sample appeared to be more uniform than in the oxidized sample, but both exhibited spacings of about 12.6 A. Chemical analysis showed no qualitative differences as a result of oxidation state. Electron diffraction patterns displayed marked differences. The pattern of the oxidized sample consisted of homogeneous rings, indicating that the stacking order in the a-b plane was turbostratic or disordered, whereas the reduced pattern exhibited much more order as evidenced by distinct spots amid low-intensity rings, suggesting that inter-layer attractive forces were stronger if Fe(II) was present in the clay crystal.

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“…The presence of clay minerals was established by X-ray diffraction studies (Table 2). These two doublets can therefore also be attributed to Fe" ions that are incorporated in the octahedral smectite layers (GOODMAN et al, 1976;ROZENSON and HELLER-KELLAI, 1977). On the basis of Mossbauer data alone, it is im possible to select one of these assignments.…”

Section: Mossbauer Spectroscopymentioning

confidence: 99%