...Ronald W. T. Wilkins; Abdul Mateen; Geoff West Abstract Nuclear magnetic resonance(NMR)and infrared spectroscopic studies of some mineral species in which the presence of oxonium ions has been postulated show that it is often difficult to obtain direct evidence of their existence. Clear evidence...

... 3 O + , K + , and NH 4 + over the water molecules sites observed in the abernathyite-like compounds may be a common feature of the interlayer structure of the hydrous layer silicates and of the intercage structure of the zeolites and clathrate compounds. The specia-nature of the oxonium ion...

... an oxonium ion, and three water molecules are distributed randomly over four H 2 O sites. To express this distribution of cations over water molecule sites the structural formulas of phases (I), (II), and (III) are written (K · 3H 2 O) (UO 2 ASO 4 ), [(NH 4 )·3H 2 O](UO 2 AsO 4 ), and [ K 1 2 ( H 3 O ) 1 2...

...) = 1.09] disappears if H + , which is 0.3737 ions per formula in excess of that required by an ideal 8H 2 O in the unit cell, is present as oxonium ion. Thermogravimetric analysis gives good agreement with TGA curves from the type locality. Ion-exchange values determined show a low-exchange capacity...

..., however, indicate that this “water” is best represented as oxonium ions (H 3 O + ) formed by interaction of the 12-coordinated interlayer H 2 O molecules with certain octahedral-layer hydroxyl groups according to the relation: H 2 O + OH − → H 3 O + + O 2 − or [ ( H 2 O ) 2 XII Mg 6 VI Si 8 VI O 20 ( OH...

.... (Traduit par la Rédaction) § E-mail address : galager@louisville.edu 07 07 2001 28 09 2000 © 2001 Mineralogical Association of Canada 2001 alunite inelastic neutron scattering crystal structure oxonium ion alunite dispersion inélastique des neutrons structure...

... data collected at HT were carried out starting from the model obtained at the immediately lower temperature. On the basis of the chemical analysis and of the thermal behaviour shown by the sample, the possible presence of oxonium (or, more specifically, hydronium) ions, H 3 O + , at the A site...

... , 1986 ; Dutrizac & Kaiman, 1976 ; Altaner et al. , 1988 ). In some earlier experiments the substitution of oxonium ion for K + is obscured by a deficiency in alkalis and an excess in H 2 O content compared to the stoichiometric composition ( Ripmeester et al. , 1986 ). The non-stoichiometric...

.... A deficiency of bases is believed to be compensated for by oxonium H 3 O (super +) ions. The natroalunite is believed to have developed under oxidizing conditions, with pyrite as the source of the SO 4 . Experiments suggest its derivation to be from aluminite. GeoRef, Copyright 2008, American Geological...

... 07 2005 24 01 2005 13 04 2005 E. Schweizerbart'sche Verlagsbuchhandlung, D-70176 Stuttgart 2005 eudialyte crystal structure oxonium. The study of natural eudialyte samples with low cationic content helps us understand ion-exchange mechanisms and the hydration...

... is an expression of the non-equivalence of the distinct H 3 O + group and the Cs position in the interlayer. The oxonium group serves to link the H 2 O-coordinated Cs ions into double chains along [010] ( Fig. 15 ). The uranyl arsenate sheets are linked by hydrogen bonding and directly by the bonds from Cs...

... ): The spectroscopic study of oxonium ions in minerals . Am. Mineral ., 59 , 811 – 819 . ...

... tetrahedral sites ( Downs et al. 1994 ). The possible locations of Type II OH are unresolved at this time [see Johnson and Rossman (2003) for a discussion of possible sites]. The H 3 O + ion (oxonium or hydronium ion) has four fundamental bands in the infrared: there are two bending modes at about...

... . American Mineralogist , 98 , 1633 – 1643 . Wilkins R.W.T Mateen A. West G.W. ( 1974 ) The spectroscopic study of oxonium ions in minerals . American Mineralogist , 59 , 811 – 819 . Wills A.S. Harrison A. ( 1996 ) Structure and magnetism of hydronium jarosite...

... through the oxygen, the cation is found to occupy a tilted orientation leading to a greater degree of disorder. Dynamical simulations indicate that the reorientation of the hydronium ions is rapid and exhibits no correlation between the cation sites. The higher level of disorder in the hydrogen positions...

... of oxonium ions (H 3 O+) in the materials. Both synthetic and natural samples are known to contain H 2 O in excess of the stoichiometric amount. Some of the excess H 2 O is generally believed to be present as H 3 O + ions substituting for the K site. INS measurements were made on two synthetic samples...

... A. ( 2008 ) Rietveld refinement and vibrational spectroscopic study of alunite from El Gnater, Central Tunisia . Russian Journal of Inorganic Chemistry , 53 , 1845 . Wilkins R.W.T. Mateen A. West G.W. ( 1974 ) The spectroscopic study of oxonium ions in minerals . American...

... anorganische Chemie , 87 , 13 – 46 . Yaroslavtsev A.B. Prozorovskaya Z.N. Tschuvayev V.F. Spicyn V.I. ( 1983 ) Mobility of oxonium ions in indium and thallium acid sulfate monohydrates . Zhurnal Neorganicheskoi Khimii , 28 , 2495 – 2498 . Xu W. Parise J. Hanson J...

... between cavansite and pentagonite; genetic implications of oxonium ion in cavansite . J. Miner. Petrol. Sci. , 104 , 241 – 252 . Kothavala R. Z. ( 1991 ): The Wagholi Cavansite locality near Poona, India . Mineral. Rec. , 22 , 415 – 420 . Larson A.C. Von Dreele R.B. ( 2000...

..., and the supernatant solution was discarded. The clay catalyst was washed with distilled water and filtered, the washing cycles are repeated until the Cl − ions disappeared from the discarded water. The clay, after drying overnight in an oven at 120°C, was finely ground in a mortar (18 g K10-Fe 3+ ). (lRS,3RS...