scholarly journals Données nouvelles sur la laumontite de la zone métamorphique de Libramont, Belgique [New mineralogical data on laumontite from the metamorphic zone of Libramont, Belgium]

1998 ◽  
Vol 1 (1-4) ◽  
pp. 3-7
Author(s):  
Frédéric Hatert
Keyword(s):  
Hydrogen Bonds ◽  
Water Content ◽  
Infrared Spectra ◽  
Chemical Analyses ◽  
Quartz Veins ◽  
Zeolitic Water ◽  
Geochemical Behaviour ◽  
Metamorphic Zone ◽  
Wet Chemical ◽  
Variable Water

New laumontite occurrences have been discovered at Bertrix, Ochamp and Luchy, in the metamorphic zone of Bastogne-Libramont. Wet chemical analyses lead to compositions close to Ca[Al2Si4O12].4H2O, with a slightly variable water content and a significant amount of potassium (up to 0.76% K2O). Infrared spectra show an ordered distribution of tetrahedral Si and Al, and relatively low hydrogen bonds between zeolitic water and crystal freamework. Laumontite crystallized in rocks fractures, under a presure lower than 3 kbar and a temperature between 170 and 280°C. The presence of albite in quartz veins and of laumontite in rocks fissures indicates a different geochemical behaviour for Na and Ca during this retrometamorphic phase.

The beryls of the Rosses district, Donegal

1971 ◽  
Vol 38 (295) ◽  
pp. 328-334 ◽  
Author(s):  
A. Hall ◽  
J. N. Walsh
Keyword(s):  
Physical Properties ◽  
Water Content ◽  
Unit Cell ◽  
Refractive Indices ◽  
Water Molecules ◽  
Chemical Analyses ◽  
Quartz Veins ◽  
Granite Complex ◽  
Alkali Elements ◽  
Variable Water

SummaryChemical analyses and physical properties are given for six samples of beryl from greisenized granites, pegmatites, and beryl-quartz veins in the Rosses granite complex. The beryls studied were all very similar in composition and contain significant amounts of alkali elements and water in addition to the constituents represented by the formula Be3Al2Si6O18. Calculation of the empirical unit cell contents indicates that most of the H2O+ is present in the mineral as water molecules. The effects of these extra constituents on the physical properties are discussed, and it is suggested that the variation in refractive indices displayed by beryl is to a large extent attributable to the variable water content.

Influence of Fining Temperature on Glass Qualities

2011 ◽  
Vol 199-200 ◽  
pp. 1906-1911
Author(s):  
Xiao Qing Liu ◽  
Jun Lin Xie
Keyword(s):  
Surface Tension ◽  
Water Content ◽  
Soda Lime ◽  
Chemical Compositions ◽  
Chemical Analyses ◽  
Ratio Increase ◽  
Tension Change ◽  
Soda Lime Silica Glass ◽  
Wet Chemical ◽  
Surface Tension Change

To study the influence of fining temperature on glass qualities, different fining temperatures from 1400°C to 1500°C were used to prepare a series soda-lime-silica glass with identical chemical compositions. Infrared spectroscopy was used to determine the water content of glass, general analyzer of melt physical properties was used to study the viscosity and surface tension change of glass melt, microscope was carried out find glass bubbles, wet chemical analyses were used to determine the Fe2+/(Fe2++Fe3+) ratio. The results show that, generally, with the increase of fining temperature, the glass melt’s water content, bubbles number and Fe2+/(Fe2++Fe3+) ratio increase, viscosity decreases. Particularly, when the fining temperature is 1450°C, the glass has lowest water content, bubbles number, Fe2+/(Fe2++Fe3+) ratio, and viscosity, and its surface tension is largest. Among all tested fining temperature, 1450°C is the optimal fining temperature.

Infrared spectra of the ammonium ion in crystals. Part VIII. Spectroscopic criteria of highly-bent hydrogen bonds

1980 ◽  
Vol 58 (9) ◽  
pp. 867-874 ◽  
Author(s):  
Osvald Knop ◽  
Wolfgang J. Westerhaus ◽  
Michael Falk
Keyword(s):  
Low Temperature ◽  
Hydrogen Bonds ◽  
Infrared Spectra ◽  
Room Temperature ◽  
Ammonium Ion ◽  
Temperature Transition ◽  
Increasing Temperature

Available evidence suggests that (1) the stretching frequencies of highly-bent hydrogen bonds decrease with increasing temperature, regardless of whether the bonds are static or dynamic in character, to a single acceptor or to several competing acceptors; and (2) departures from symmetric trifurcation (or bifurcation) toward asymmetric situations lower the stretching frequency. In further support of these criteria isotopic probe ion spectra between 10 K and room temperature have been obtained for taurine and for trigonal (NH4)2MF6 (M = Si, Ge, Sn, Ti). Evidence of a low-temperature transition at 100(10) K in trigonal (NH4)2SnF6 is presented, and existence of the previously reported transition at 38.6 K in trigonal (NH4)2SiF6 is confirmed. Symmetry changes associated with these transitions are discussed.

Chemical Synthesis and Properties of Layered Co1-yNiyO2-δOxides (0≤y≤1)

2000 ◽  
Vol 658 ◽  
Author(s):  
A. Manthiram ◽  
R. V. Chebiam ◽  
F. Prado
Keyword(s):  
Layer Structure ◽  
Magnetic Data ◽  
Chemical Analyses ◽  
X Ray Diffraction ◽  
Absorption Bands ◽  
X Ray ◽  
Ni Content ◽  
Wet Chemical ◽  
Oxide Ions ◽  
Structure Layer

ABSTRACTLayered Co1-yNiyO2-δ oxides with 0≤y≤1 have been synthesized by chemically extracting lithium from LiNi1-yCoyO2 with NO2PF6 at ambient temperature. The samples have been characterized by X-ray diffraction, wet-chemical analyses, infrared spectroscopy, and magnetic susceptibility measurements. While NiO2-δ retains the initial O3 (CdCl2 structure) layer structure of LiNiO2, CoO2-δ consists of a mixture of P3 and O1 (CdI2 structure) phases that are formed by a sliding of the oxide ions in the initial O3 structure. CoO2-δ and NiO2-δ have oxygen contents of, respectively, 1.67 and 1.95 and the oxygen content increases with increasing Ni content, y, in Co1-yNiyO2-δ. While CoO2-δ exhibits metallic conductivity as revealed by theabsence of absorption bands in the infrared spectrum, NiO2-δ exhibits semiconducting behavior due to a completely filled t2g band. Magnetic data reveal a transition from antiferromagnetic to ferromagnetic correlations as the Ni content in Co1-yNiyO2-δ increases.

Octahedral occupancy and the chemical composition of diagenetic (low-temperature) chlorites

Clay Minerals ◽  
1991 ◽  
Vol 26 (2) ◽  
pp. 149-168 ◽  
Author(s):  
S. Hillier ◽  
B. Velde
Keyword(s):  
Chemical Composition ◽  
Low Temperature ◽  
Bulk Composition ◽  
Compositional Variation ◽  
Low Grade ◽  
Chemical Analyses ◽  
Method Of Calculation ◽  
Sedimentary Sequences ◽  
Wet Chemical ◽  
Potential Use

AbstractThe chemical composition of about 500 diagenetic chlorites, determined by electron microprobe, has been studied in six different sedimentary sequences spanning conditions from early diagenesis to low-grade metamorphism, in the temperature range 40–330°C. The range of Fe/(Fe + Mg) is almost complete and is positively correlated with Al. Five sequences show the same compositional variation. In each, the most siliceous chlorites have the lowest R2+, substantially more octahedral than tetrahedral Al, and the lowest octahedral totals. Conversely, the least siliceous have the highest R2+, nearly equal octahedral and tetrahedral Al, and octahedral totals close to that for an ideal trioctahedral mineral. A dioctahedral substitution Si[]R2−2 (where [] represents a vacant octahedral site) which decreases with temperature, describes this variation. Low octahedral totals are, however, induced by the method of calculation and need not indicate vacancies; for published wet chemical analyses of metamorphic chlorites they may simply indicate oxidation of Fe. Intergrown dioctahedral phyllosilicates may partly account for apparent vacancies in diagenetic chlorites. Nevertheless, the correlation of composition with temperature and similarities to the temperature-related evolution of synthetic chlorites, suggest that diagenetic chlorites are compositionally distinct from, but metastable with respect to, fully trioctahedral metamorphic chlorites. Temperature-related trends are modified by bulk composition, complicating their potential use for low-temperature geothermometry.

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