Phase Equilibria in the System NaAlSi3O8–NaAlSiO4–H2O with Special Emphasis on the Stability of Analcite

1971 ◽  
Vol 8 (3) ◽  
pp. 311-337 ◽  
Author(s):  
Ki-Tae Kim ◽  
B. J. Burley
Keyword(s):  
Solid Solution ◽  
Phase Equilibria ◽  
Phase Diagrams ◽  
Solid Solutions ◽  
Singular Points ◽  
Phase Relations ◽  
The Other ◽  
Stability Field ◽  
Narrow Zone ◽  
The Stability

Phase equilibria were determined in the P–T range of 0.5–10 Kb and 150–900 °C in the system NaAlSi3O8 – NaAlSiO4 – H2O. Two isobaric (2 Kb and 5.15 Kb) T–X phase diagrams (projected to a dry base) were completely determined and show that the stability field of analcite solid solutions has a large distorted pentagonal shape. The phase relations for the transition: nepheline hydrate I [Formula: see text] nepheline + H2O on the composition join NaAlSiO4 – H2O are not binary. It was found that there exists a narrow zone for the transition. The true P–T curve was found and determined in terms of a ternary univariant reaction: nepheline hydrate I + analcite [Formula: see text] nepheline + H2O. In the system NaAlSi3O8 – SiO2 – H2O, albite contains about 5 wt % silica in solid solution at 5.15 Kb and 670 °C.The equilibrium compositions of various univariant phases were determined essentially on the basis of the T–X phase diagrams. Another univariant reaction (zeolite species P = analcite + nepheline – hydrate I + H2O) was found at 2 Kb/215 °C and 5.15 Kb/235 °C and determined on a P–T projection. Three singular points were determined; two of them are located at 0.8 Kb/390 °C and 9.4 Kb/475 °C respectively on a univariant P–T curve for the reaction nepheline hydrate I + analcite = nepheline + H2O; the other one is located at 6 Kb/655 °C on a univariant P–T curve along which nepheline, analcite, liquid, and vapor coexist. The petrogenetic implication of analcite is discussed fully.

Zur Chemie von Mischphasen in komplexen Zustandsdiagrammen Das System Bi2O3/Bi2Se3/Bi2Te3/Chemistry of Mixed Crystals in Complex Phase Diagrams The System Bi2O3/Bi2Se3/Bi2Te3

2000 ◽  
Vol 55 (7) ◽  
pp. 627-637 ◽  
Author(s):  
P. Schmidt ◽  
H. Oppermann
Keyword(s):  
Phase Diagram ◽  
Solid Solution ◽  
Phase Diagrams ◽  
Thermodynamic Modeling ◽  
Solid Solutions ◽  
Thermodynamic Data ◽  
Phase Relations ◽  
Mixed Crystals ◽  
Complex Phase ◽  
Quaternary Solid Solution

Abstract Pseudoternary System Bi2O3/Bi2Se3/Bi2Te3, Phase Diagram, Thermodynamic Data The phase diagram of the pseudoternary system Bi2O3/Bi2Se3/Bi2Te3 is found to include a quaternary solid solution Bi2O2 (TexSe1-x) and ternary, intermetallic mixed crystals Bi2(TexSe1-x)3. Using thermodynamic modeling of the solid solutions it is possible to calcu­ late complex heterogeneous equilibria between all phases of this phase diagram. As a result we can thermodynamically describe the observed phase relations:Bi2(TexSe1-x)3 ⊿H°m(298) = 0; ⊿S°m(298) = R[xlnx + (1-x)ln(1-x)]Bi2O2(TexSe1-x) ⊿H°m(298) = Ω · x(1-x); O⊿S°m(298) = R/4 [xlnx + (1-x)ln(1-x)]Ω = 0,6 kcal/mol

A further study of analcime solid solutions in the system NaAlSi3O8-NaAISiO4-H20, with particular note of an analcime phase transformation

1980 ◽  
Vol 43 (332) ◽  
pp. 1035-1045 ◽  
Author(s):  
Ki-Tae Kim ◽  
B. J. Burley
Keyword(s):  
Phase Transition ◽  
Solid Solution ◽  
Phase Transformation ◽  
Solid Solutions ◽  
Total Pressure ◽  
Room Temperature ◽  
Water Pressure ◽  
Stability Field ◽  
Cell Parameters ◽  
The Stability

SummaryThe stability field of analcime solid solutions in the system NaAlSi3O8-NaAlSiO4-H2O has been previously determined by Kim and Burley (1971a). These experiments are re-examined with a view to determining the variations of the room-temperature cell parameters of analcime as a function of temperature of synthesis and composition. It is shown from this evidence that most of the analcime solid solutions in these experiments are equilibrium compositions. The increase in the cell dimension of quenched analcime solid solution is found to be 5 × 10−5 Å/°C. It is suggested that birefringence in analcime is induced by low water-pressure relative to total pressure. A phase transition appears to be observed in quenched analcimes of this study and is thought to be the same as that in the Golden analcime reported by Yoder and Weir (1960).

Spinel solid solutions in the systems MgAl2O4–ZnAl2O4 and MgAl2O4–Mg2TiO4

1997 ◽  
Vol 12 (10) ◽  
pp. 2584-2588 ◽  
Author(s):  
M. A. Petrova ◽  
G. A. Mikirticheva ◽  
A. S. Novikova ◽  
V. F. Popova
Keyword(s):  
Solid Solution ◽  
Phase Diagrams ◽  
Melting Temperature ◽  
Solid Solutions ◽  
Spinel Structure ◽  
Room Temperature ◽  
Binary Systems ◽  
Continuous Series ◽  
X Ray ◽  
Spinel Solid Solutions

Phase relations in two binary systems MgAl2O4–ZnAl2O4 and MgAl2O4–Mg2TiO4 have been studied and phase diagrams for them have been constructed. Based on the data of x-ray phase and crystal-optical analyses, the formation of a continuous series of solid solutions with spinel structure between the terminal members of the systems studied has been established. In the MgAl2O4–ZnAl2O4 system the solid solution is stable in the range from room temperature to melting temperature. In the MgAl2O4–Mg2TiO4 system the solid solution decomposes below 1380 °C, yielding the formation of limited regions of homogeneity on the basis of MgAlM2O4 and Mg2+2δ Ti1–δO4. Decomposition of the solid solution is accompanied by crystallization of MgTiO3.

An EXAFS study of cation site distortions through the P2/c-P1̄ phase transition in the synthetic cuproscheelite-sanmartinite solid solution

1994 ◽  
Vol 58 (391) ◽  
pp. 185-199 ◽  
Author(s):  
P. F. Schofield ◽  
J. M. Charnock ◽  
G. Cressey ◽  
C. M. B. Henderson
Keyword(s):  
Phase Transition ◽  
Solid Solution ◽  
Stability Field ◽  
Cation Site ◽  
Cu Content ◽  
Square Planar ◽  
Jahn Teller ◽  
Exafs Study ◽  
Four Square ◽  
The Stability

AbstractEXAFS spectroscopy has been used to monitor changes in divalent cation site geometries across the P2/c-P1̄ phase transition in the sanmartinite (ZnWO4)-cuproscheelite (CuWO4) solid solution at ambient and liquid nitrogen temperatures. In the ZnWO4 end member, Zn occupies axially-compressed ZnO6 octahedra with two axial Zn-O bonds at approximately 1.95 Å and four square planar Zn-O bonds at approximately 2.11 Å. The substitution of Zn by Cu generates a second Zn environment with four short square planar Zn-O bonds and two longer axial Zn-O bonds. The proportion of the latter site increases progressively as the Cu content increases. Cu EXAFS reveals that the CuO6 octahedra maintain their Jahn-Teller axially-elongate geometry throughout the majority of the solid solution and only occur as axially-compressed octahedra well within the stability field of the Zn-rich phase with monoclinic long-range order.

The Bismuth-Barium Oxides

1998 ◽  
Vol 547 ◽  
Author(s):  
K. Müller ◽  
J.K. Meen ◽  
D. Elthon
Keyword(s):  
Solid Solution ◽  
High Temperature ◽  
Low Temperature ◽  
Phase Relations ◽  
The Other ◽  
Face Centered Cubic ◽  
Polymorphic Transformations ◽  
Face Centered ◽  
T Phase

AbstractPhase relations have been determined for the Bi-Ba oxide pseudobinary up to 50 cat % Ba in 1 atm of oxygen at 640°-1000°C. The low-temperature α-Bi2O3 polymorph does not dissolve appreciable BaO. All other phases in the system have significant ranges of solution. The δ-Bi2O3 polymorph, stable from 730°C to 825°C is an end-member of a face-centered cubic solid solution (FCCss) that dissolves up to 2.7 % Ba. Ba-saturated FCCss and Bi-saturated rhombohedral (ß) solid solution (6.3 % Ba) melt at a eutectic at 753 °C. Less Bi is needed to saturate the ß phase at lower temperatures so α-Bi2O3 coexists with a ß phase containing 11.5 % Ba at 646°C.The amount of Ba required to saturate the ß phase depends less strongly on temperature. Ba-saturated ß phase contains 19 % Ba at 700°C. These ß materials are in equilibrium with an oxide near Bi3BaO5.5 that undergoes two polymorphic transformations: low-temperature cubic (<700°C); orthorhombic (700-730°C); high-temperature cubic (Cht). There is a eutectic between the ß and Cht, at 775±6°C. At T<700°C, 26.5 % Ba saturates the latter but it can take in up to 29.5 % Ba (at 812°C). At T<815°C the coexisting phase is BiBaO3. A tetragonal (T) phase forms by reaction of Ch, and BiBaO3 and has ~35% BaO at 815°C. The composition span of T widens as temperature increases. Cht, melts incongruently at 820°C to a liquid and T with 29.8 % Ba. Above that temperature the Bi-saturated and Ba-saturated T phases both become more Ba-rich as temperature is elevated. T melts incongruently to liquid and BiBaO3.The δ-Bi2O3 and ß, both anion conductors, have structures based on that of fluorite. The other oxides have perovskite-like structures. Half of the Bi in BiBaO3 is pentavalent and half is trivalent. The other oxides appear to have all their Bi in the 3+ state.

Modifications 7 And 8 Of Decagonal AI-Co-Ni

1998 ◽  
Vol 553 ◽  
Author(s):  
S. Ritsch ◽  
K. Hiraga ◽  
C. Beeli ◽  
T. Gödecke ◽  
M. Scheffer ◽  
...  
Keyword(s):  
Rotation Axis ◽  
The Other ◽  
Stability Field ◽  
One Dimensional ◽  
Decagonal Phase ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
The Stability ◽  
Means Of Transmission ◽  
Very High

AbstractBesides the six established decagonal states of the Al-Co-Ni quasicrystal two more modifications have been discovered by means of transmission electron microscopy. One is a pentagonal quasicrystal with a superstructure found in specimens with a very high Co-content and quenched from the highest possible temperature lying within the stability field of decagonal Al-Co-Ni. Its electron diffraction patterns are characterized by a 5-fold rotation axis as a unique symmetry element as well as superstructure reflections similar to those of a related decagonal phase. The other is a one-dimensional quasicrystal closely related to decagonal Al-Co-Ni. The modulation length of 61 Å along the periodic direction in its pseudo 10-fold diffraction patterns can be assumed to be caused by a strong linear, uniform, phason strain in the material.

scholarly journals Phase equilibria in the YFeO3 – YСoO3 system in air

2021 ◽  
Vol 8 (1) ◽  
pp. 20218108
Author(s):  
A. V. Bryuzgina ◽  
A. S. Urusova ◽  
I. L. Ivanov ◽  
V. A. Cherepanov
Keyword(s):  
Phase Diagram ◽  
Solid Solution ◽  
Phase Equilibria ◽  
Spin State ◽  
Solid Solutions ◽  
Homogeneity Range ◽  
Perovskite Structure ◽  
Single Phase ◽  
Decomposition Temperature ◽  
Unusual Behavior

YFe1-xСоxO3 solid solutions were prepared by glycerol-nitrate technique. The homogeneity range of solid solutions was studied within the temperature range 1173 – 1573 K. A continues series of solid solution below the decomposition temperature of YСоO3, which was shown to be equal to 1266 ± 6 K, begins to narrow at higher temperatures and becomes equal to 0 ≤ x ≤ 0.1 at 1573 K. The phase diagram of the YFeO3 – YСoO3 system in the “T – composition” coordinates was divided into three fields. Similar to the parent ternary oxides, all single-phase YFe1-xСоxO3 solid solutions possess orthorhombically distorted perovskite structure (Pnma space group). Unusual behavior of orthorhombic distortions in YFe1-xСоxO3 with temperature was explained by probable changes in spin state of Co3+ ions.

scholarly journals Study of silica-undersaturated magmas through the Kalsilite- Nepheline-Diopside-Silica system at 4.0 GPa and dry conditions

2018 ◽  
Vol 18 (2) ◽  
pp. 87-102
Author(s):  
Márcio Roberto Wilbert de Souza ◽  
Rommulo Vieira Conceição ◽  
Daniel Grings Cedeño ◽  
Roberto Vicente Schmitz Quinteiro
Keyword(s):  
High Pressure ◽  
Solid Solutions ◽  
Negative Correlation ◽  
Stability Field ◽  
Thermal Barrier ◽  
High Pressure And Temperature ◽  
Alkaline Magma ◽  
Magma Genesis ◽  
Dry Conditions ◽  
The Stability

This study experimentally investigates the Kalsilite-Nepheline-Diopside-Silica system at high pressure and temperature, with emphasis on silica-undersaturated volume (leucite-nepheline-diopside — Lct-Nph-Di; and kalsilite-nepheline-diopside — Kls + Nph + Di — planes), at 4.0 GPa (~120 km deep), temperatures up to 1,400ºC and dry conditions, to better understand the influence of K2O, Na2O, and CaO in alkali-rich silica-undersaturated magma genesis. In the Lct-Nph-Di plane, we determined the stability fields for kalsilite (Klsss), nepheline (Nphss) and clinopyroxene (Cpxss) solid solutions, wollastonite (Wo) and sanidine (Sa); and three piercing points: (i) pseudo-eutectic Kls + Nph + Di + liquid (Lct62Nph29Di9) at 1,000ºC; (ii) Kls + Sa + (Di + Wo) + liquid (Lct75Nph22Di2) at 1,200ºC; and (iii) pseudo-eutectic Kls + Di + Wo + liquid (Lct74Nph17Di9) at 1,000ºC. Kalsilite stability field represents a thermal barrier between ultrapotassic/potassic vs. sodic compositions. In the plane Kls-Nph-Di, we determined the stability fields for Klsss, Nphss and Cpxss and two aluminous phases in smaller proportions: spinel (Spl) and corundum (Crn). This plane has a piercing point in Kls + Nph + Di(± Spl) + liquid (Kls47Nph43Di10) at 1,100ºC. Our data showed that pressure extends K dissolution in Nph (up to 39 mol%) and Na in Kls (up to 27 mol%), and that these solid solutions, if present, determinate how much enriched in K and Na an alkaline magma will be in an alkaline-enriched metasomatic mantle. Additionally, we noted positive correlation between K2O and SiO2 concentration in experimental melts, negative correlation between CaO and SiO2, and no evident correlation between Na2O and SiO2. 

Olivenite-Adamite Solid Solution From Oxidation Zone in Rędziny (West Sudetes, Poland)

Mineralogia ◽  
2006 ◽  
Vol 37 (2) ◽  
pp. 101-110 ◽  
Author(s):  
Boźena Gołębiowska ◽  
Adam Pieczka ◽  
Wojciech Franus
Keyword(s):  
Solid Solution ◽  
Carbonate Rocks ◽  
Oxidation Zone ◽  
Stability Field ◽  
Mineral Phases ◽  
West Sudetes ◽  
Polymetallic Mineralization ◽  
The Stability ◽  
Weathering Zone ◽  
Ubiquitous Presence

Olivenite-Adamite Solid Solution From Oxidation Zone in Rędziny (West Sudetes, Poland)An extensive hydrothermal polymetallic mineralization with a well developed oxidation zone rich in secondary minerals occurs in dolostones several hundred meters from the Karkonosze granite at Rędziny. Using XRD and FTIR methods, mineral phases representing transitional members of the olivenite-adamite solid solution have been identified. Electron microprobe analyses reveal the most common varieties to be zincian olivenite and cuprous adamite with compositions ranging from (Cu1.17Zn0.83)(AsO4)(OH) to (Zn1.38Cu0.62)(AsO4)(OH). The two minerals are subordinate in the weathering zone which can be characterized as having been a zone of low Cu2+and Zn2+activity and with mineralizing solutions of increased pH. A high Ca2+concentration due to the ubiquitous presence of carbonate rocks resulted in the expansion of the stability field of another arsenate, conichalcite (or Zn-bearing conichalcite), which is a common mineral there.

Equilibrium phase relations in the Bi–Ca–Sr–Cu–O system at 850 and 900°C

1990 ◽  
Vol 5 (7) ◽  
pp. 1403-1408 ◽  
Author(s):  
C-L. Lee ◽  
J-J. Chen ◽  
W-J. Wen ◽  
T-P. Perng ◽  
J-M. Wu ◽  
...  
Keyword(s):  
Solid Solution ◽  
Powder Diffraction ◽  
Equilibrium Phase ◽  
Superconducting Phase ◽  
Phase Relations ◽  
The Other ◽  
Boundary Line ◽  
X Ray ◽  
Tie Lines ◽  
Boundary Lines

The phase relations of equilibrium compounds in the pseudoternary system Bi2O3–(Ca,Sr)O–CuO at 850 and 900°C were studied. The ratio of Ca : Sr was fixed at 1:2. Starting materials of Bi2O3, CaCO3, SrCO3, and CuO with various ratios were mixed, pressed into pellets, and heated at or above and then brought back to 850 or 900°C for different durations to ensure that equilibrium had been reached. The products were cooled in air or quenched in liquid nitrogen and then identified by x-ray powder diffraction. At 850°C, only the superconducting phase, Bi2CaSr2Cu2Ox (2122), was observed inside the triangle. The other stable phases were all positioned on the boundary lines, and included CuO·⅗MO, CuO·MO, CuO·2MO, 1.½Bi2O3·0.9MO, Bi2O3·4MO, Bi2O3·9MO, and a solid solution, Bi2O3·xMO, where 0.16  x  0.82 and MO represents ⅓(CaO·2SrO). At 900°C, the above boundary line phases remained stable but the 2122 phase was not observed. The tie lines among the stable phases in the two isotherms were established.

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