Results 91 to 100 of about 177 (132)

The crystal chemistry of stilbites and stellerites

Bulletin de Minéralogie, 1978
A total of 65 samples of stilbite and stellerite have been chemically analyzed and X-rayed. By using F-unit cell also for monoclinic stilbites, the lattice constants ranges are : a = 13.570-13.605 Â, b = 18. 198-18.270 Â, c = 17.823-17.863 Â for stellerites, and a = 13.595-13.657 À, b = 18. 197-18.309 Â, c = 17.775-17.842 Â, β = 90.
Passaglia, Elio, Galli, Ermanno, Leoni, Leonardo, Rossi, Giuseppe   +3 more
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Synthesis of stilbite by the hydrothermal method

Journal of Physics D: Applied Physics, 1998
The effect of temperature on stilbite synthesis was investigated systematically in the temperature range 80-C by hydrothermal treatment of artificial glasses of the same composition (1O-8CaO-9O) at 1 kbar O pressure. The zeolite was always formed with monoclinic symmetry (, a = 13.61 A, b = 18.24 A, c = 11.27 A and ; or , a = 13.61 A, b = 18.24 A, c ...
H Ghobarkar, O Schäf
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Thermodynamic properties of the zeolite stilbite

Zeolites, 1990
In this study, calorimetric measurements of the molar enthalpy of formation Δ f H 0 m at 298.15 K, molar heat capacity C 0 p,m (and, thus, the molar entropy 7 S 0 m ) from 5 to 350 K, and enthalpy increments H 0 m ( T ) — H 0 m (298.15 K) from 350 to 500 K were performed on a specimen of stilbite characterized by electron ...
D.A. Howell, G.K. Johnson, I.R. Tasker, P.A.G. O'Hare, W.S. Wise   +4 more
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Thermal behaviour of natural stilbite crystals

Thermochimica Acta, 1982
Abstract Observations of the behaviour of natural stilbite crystals on dehydration are reported. Results of TG, DTA, static weight loss measurements, X-ray diffractometric analysis and IR studies are described and interpreted. It is established that the stilbite structure collapses at about 400°C.
M.S. Joshi, P.Mohan Rao, A.L. Choudhari, R.G. Kanitkar   +3 more
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THERMAL TRANSFORMATIONS OF STILBITE

Canadian Journal of Earth Sciences, 1966
Stilbite samples from two localities were examined. Preliminary D.T.A. and T.G.A. investigations to 1 400 °C were followed by high temperature diffractometry. Debye–Scherrer and Guinier techniques were used to study cooled samples, Diffractometer and single crystal data were processed with a computer to calculate cell parameters and thermal expansion ...
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Stilbite-laumontite equilibrium

Contributions to Mineralogy and Petrology, 1971
The reaction stilbite=laumontite+3 quartz+3 H2O was experimentally studied using conventional hydrothermal techniques employing mineral mixtures consisting of reactants and products in 9∶1 and 1∶9 ratios. Equilibrium was demonstrated; the univariant curve passes through about 170° C and 2000 bars, 185°±10° C and 3000 bars, about 185° C and 4000 bars ...
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The relation of stellerite and epidesmine to stilbite

Mineralogical Magazine and Journal of the Mineralogical Society, 1939
The recent finding of a stellerite-like mineral in California has led to this study of its relations to epidesmine and stilbite. The mineral was found by Mr. Allen Nichol, mineralogist of the Division of Highways, in the quarry of the Calavera Materials Company near Oceanside, San Diego County.
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Microporous Stilbite single crystals for alcohol sensing

Journal of Electroceramics, 2006
The possibility of shape-selective resistive gas sensors for polar molecules using the microporous alumo-silicate Stilbite is investigated. The electrical impedance of natural Stilbite single crystals at 80°C decreases in presence of methanol, 2-propanol and 3-pentanol, but increases with increasing water and neo-pentanol vapour pressure.
Schäf, O., Wernert, V., Ghobarkar, H., Knauth, P.   +3 more
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Solid solutions of stilbite and epistilbite

Inorganic Materials, 2015
Analysis of the empirical compositions of stilbite-Ca and epistilbite from various occurrences has shown that these solid solutions differ primarily in the mole fraction of water in their compositions. A comparative analysis of different structural models of stilbite (C2/m, F 2/m (42℃), and Amma (168℃)) revealed no fundamental distinctions between the ...
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Thermochemical study of calcium zeolites—heulandite and stilbite

American Mineralogist, 2001
Calorimetric measurements were made on natural samples of heulandite having the composition Ca0.86Na0.37K0.06Al2.14Si6.86O18·6.1H2O and stilbite Ca1.01Na0.12Al2.12Si6.88O18·7.27H2O both from the same locality (Nidym River, E. Siberia, Russia). Enthalpies of formation and hydration were studied by calorimetry in lead borate solvent at 975 K.
I. Kiseleva, A. Navrotsky, I. Belitsky, B. Fursenko   +3 more
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