Subsolidus phase relations of the SrO–WO3–CuO system at 800°C in air

Grivel, Jean‐Claude; Norby, Poul

doi:10.1016/j.jallcom.2011.09.104

Cited by 11 publications

(8 citation statements)

References 45 publications

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“…The AP phase likely becomes less stable under pressure because Coulomb repulsion between the highly charged W ions becomes stronger as the distance between them shortens. Indeed, Sr 3 W 2 O 9 , which would have smaller unit cells if it existed, is not obtainable; attempts to synthesize this compound under ambient pressure have resulted in mixtures of Sr 2 WO 5 and SrWO 4 based on the Sr–W–O ternary phase diagram . Thus, it is unexpected that the AP phase converts to the HP phase because the Ba–W–O ternary phase diagram also includes Ba 2 WO 5 and BaWO 4 .…”

Section: Discussionmentioning

confidence: 99%

Discovery of the High-Pressure Phase of Ba₃W₂O₉ and Determination of Its Crystal Structure

Urushihara¹,

Asaka²,

Fukuda³

et al. 2017

Inorg. Chem.

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A new polymorphism of BaWO is discovered with the use of a high-pressure synthesis technique and its crystal structure is determined by single-crystal X-ray diffraction and transmission electron microscopy. The crystal structure was isostructural with that of BaReO, having a hexagonal unit cell of R3̅m symmetry with a = 0.574060(10) nm and c = 2.08256(4) nm. The high-pressure (HP) phase is obtained from a transformation of an ambient-pressure (AP) phase of the compound, which has the CsTlCl-type structure. The most notable change in the transformation is the connection of WO octahedra. The HP phase has corner-sharing octahedra, which form a bilayer structure, while the AP phase has face-sharing octahedra of isolated [WO] dimers. This type of the structural phase transition is unreported although it is possibly that a sequence of high-pressure structural transformations occurs for similar chemical compositions. The HP phase has W ions in WO octahedra with an unusual off-center displacement; although the displacement is slightly relaxed compared with that of the AP phase. The off-center displacement suggests strong hybridization between the W 5d orbitals and O 2p orbitals.

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Section: Discussionmentioning

confidence: 99%

Discovery of the High-Pressure Phase of Ba₃W₂O₉ and Determination of Its Crystal Structure

Urushihara¹,

Asaka²,

Fukuda³

et al. 2017

Inorg. Chem.

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“…Excess CaO or WO 3 in the respective starting compositions of these phases systematically results in the appearance of impurities, while the cell parameters of the main phases are not affected. Similar considerations are valid for the WO 3 and CaO end compounds. None of these phases appears to form an extended solid solution and our results are therefore in agreement with the data published in Ref 20.…”

Section: Wo 3 -Caomentioning

confidence: 56%

“…High purity WO 3 , CaCO 3 and CuO, powders (all ‡99.9%) were thoroughly mixed in an agate mortar. In total, 46 samples with various nominal compositions were studied.…”

Section: Methodsmentioning

confidence: 99%

“…In contrast, whereas a few RE 2 O 3 -CaO-CuO (RE = rare earth) systems were explored, [1,2] the pseudoternary systems including CaO, CuO and a transition element oxide have been poorly investigated. During a recent study of the SrO-WO 3 -CuO system at 800°C in air [3] a new ternary oxide compound with Sr 8 CuW 3 O 18 composition was discovered besides the already known Sr 2 WCuO 6 . [4] Since no Ca equivalent to these compounds are known, the phase equilibria of the CaO-WO 3 -CuO system under similar conditions were determined in order to explore the possible occurrence of new cuprate compounds.…”

Section: Introductionmentioning

confidence: 99%

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Subsolidus Phase Relations of the CaO-WO3-CuO System at 800 °C in Air

Grivel

2012

J. Phase Equilib. Diffus.

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The subsolidus phase relations of the CaO-WO 3 -CuO system were investigated in air. The samples were equilibrated at 800°C. Under these conditions, five binary oxide phases are stable: Ca 2 CuO 3 , Cu 3 WO 6 , CuWO 4 , CaWO 4 and Ca 3 WO 6 . The pseudo-ternary section is characterised by 6 three-phase regions. No Ca equivalents to the Sr 2 CuWO 6 , Ba 2 CuWO 6 or Sr 8 CuW 3 O 18 phases were formed.

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“…Nevertheless, whereas ternary sections involving these oxides with rare-earth oxides have been systematically determined (refe rence [2] and references therein), combinations of CuO and (BaO, SrO or CaO) with a transition metal oxide are still poorly investi-gated. In the case of SrO, the exceptions encompass systems in which the transition element is V [3], Nb [4,5], Fe [6], Ti [7,8], Zr [8], Hf [8], Ta [9], W [10] and Co [11]. The CuO -SrO -ZnO system does not appear to have been stu died.…”

Section: Introductionmentioning

confidence: 99%

Subsolidus phase equilibria of the CuO – SrO – ZnO pseudoternary system in air at 900 °C

Grivel

2017

Chim.Tech.Acta

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The subsolidus phase equilibria of the CuO-SrO-ZnO system were determined at 900 °C in air. The pseudoternary section does not contain ternary oxide phases but is made of 5 three-phase regions and 2 narrow two-phase regions linked to a Sr 14 Cu 24-x Zn x O 41-y solid solution. The maximum solubility of Zn in this phase is limited to x ≈ 0.1, but this low doping level results in a significant decrease of the electrical resistivity by about one order of magnitude compared to the undoped compound. The other binary oxide phases SrZnO 2 , Sr 2 CuO 3 , and SrCuO 2 do not form solid solutions extending into the ternary system. SrZnO 2 was found to decompose upon contact with ambient air.

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Subsolidus phase relations of the SrO–WO3–CuO system at 800°C in air

Cited by 11 publications

References 45 publications

Discovery of the High-Pressure Phase of Ba₃W₂O₉ and Determination of Its Crystal Structure

Discovery of the High-Pressure Phase of Ba₃W₂O₉ and Determination of Its Crystal Structure

Subsolidus Phase Relations of the CaO-WO3-CuO System at 800 °C in Air

Subsolidus phase equilibria of the CuO – SrO – ZnO pseudoternary system in air at 900 °C

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Subsolidus phase relations of the SrO–WO3–CuO system at 800°C in air

Cited by 11 publications

References 45 publications

Discovery of the High-Pressure Phase of Ba3W2O9 and Determination of Its Crystal Structure

Discovery of the High-Pressure Phase of Ba3W2O9 and Determination of Its Crystal Structure

Subsolidus Phase Relations of the CaO-WO3-CuO System at 800 °C in Air

Subsolidus phase equilibria of the CuO – SrO – ZnO pseudoternary system in air at 900 °C

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Discovery of the High-Pressure Phase of Ba₃W₂O₉ and Determination of Its Crystal Structure

Discovery of the High-Pressure Phase of Ba₃W₂O₉ and Determination of Its Crystal Structure