Materials discovery by crystal growth: Lanthanide metal containing oxides of the platinum group metals (Ru, Os, Ir, Rh, Pd, Pt) from molten alkali metal hydroxides

Mugavero, Samuel J.; Gemmill, William R.; Roof, Irina P.; Loye, Hans-Conrad zur

doi:10.1016/j.jssc.2009.05.006

Cited by 67 publications

(55 citation statements)

References 142 publications

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“…Our group has focused on employing hightemperature solutions of alkali metal hydroxides and has been successful in synthesizing new oxides as well high-quality single crystals of known compositions and structures [13][14][15][16][17]. The acidbase chemistry of hydroxide melts is best described by the LuxFlood concept of oxoacidity [18,19], where the autodissociation of the hydroxide yields the H 2 O as an acidic species and O 2 À as a basic species (Eq.…”

Section: Introductionmentioning

confidence: 99%

Crystal growth of K2UO4 and Na4UO5 using hydroxide fluxes

Roof

Smith

Loye

2010

Journal of Crystal Growth

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Section: Introductionmentioning

confidence: 99%

Crystal growth of K2UO4 and Na4UO5 using hydroxide fluxes

Roof

Smith

Loye

2010

Journal of Crystal Growth

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“…The flux can be nonreactive or reactive; in the latter case the flux itself becomes incorporated into the product (7,8). This wellestablished approach has demonstrated the prolific discovery of novel inorganic materials grown out of low-melting fluxes, from oxides and other chalcogenides (9)(10)(11)(12), to pnictides (13,14), to intermetallics (15), many of which cannot be attained by direct combinations of the elements. Despite the variety of metastable phases formed in these reactions, the classical approach is to predetermine a given set of reaction conditions (e.g., time, temperature, and heating and cooling rates) and wait for completion to isolate and identify the formed compounds.…”

mentioning

confidence: 99%

In situ studies of a platform for metastable inorganic crystal growth and materials discovery

Shoemaker

Chung

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

134

152

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Rapid shifts in the energy, technological, and environmental demands of materials science call for focused and efficient expansion of the library of functional inorganic compounds. To achieve the requisite efficiency, we need a materials discovery and optimization paradigm that can rapidly reveal all possible compounds for a given reaction and composition space. Here we provide such a paradigm via in situ X-ray diffraction measurements spanning solid, liquid flux, and recrystallization processes. We identify four new ternary sulfides from reactive salt fluxes in a matter of hours, simultaneously revealing routes for ex situ synthesis and crystal growth. Changing the flux chemistry, here accomplished by increasing sulfur content, permits comparison of the allowable crystalline building blocks in each reaction space. The speed and structural information inherent to this method of in situ synthesis provide an experimental complement to computational efforts to predict new compounds and uncover routes to targeted materials by design.D iscovering new materials is a crucial step to address largescale problems of energy conversion, storage, and transmission and other technological needs whether seeking bulk phases or thin films. Dense inorganic materials are desired for their tunable transport, magnetism, optical absorption, and stability, but their existence in general cannot be predicted with the near certainty of that of metastable organic and organometallic compounds. Whereas the desire to efficiently locate and assemble inorganic materials is great, it is hindered by traditional solid-state synthetic methods-at high temperatures often only the energy-minimum thermodynamic product is obtained. To strive toward an arena where metastable compounds can be discovered rapidly and made systematically, here we conduct reactions within liquid fluxes and use in situ monitoring to capture signatures of new phases, even when they quickly dissolve in the melt.Convective liquid fluxes (salts, metals, or oxides) can serve as reaction media that aid diffusion and enable rapid formation of compounds at temperatures far below their melting points (1-6). The flux can be nonreactive or reactive; in the latter case the flux itself becomes incorporated into the product (7,8). This wellestablished approach has demonstrated the prolific discovery of novel inorganic materials grown out of low-melting fluxes, from oxides and other chalcogenides (9-12), to pnictides (13,14), to intermetallics (15), many of which cannot be attained by direct combinations of the elements. Despite the variety of metastable phases formed in these reactions, the classical approach is to predetermine a given set of reaction conditions (e.g., time, temperature, and heating and cooling rates) and wait for completion to isolate and identify the formed compounds. It is not possible to observe how the reaction system itself has arrived at the isolated compound, whether the crystalline material formed on heating, on cooling, or on soaking at the given high temperature,...

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“…[1] There are also some good review articles. [2][3][4] Crystal growth and materials exploration from metallic flux were mainly developed in recent years with a major contribution from P. C. Canfield and Z. Fisk. [4][5][6][7][8][9][10][11][12] Compared to the flux growth of oxides which is normally performed in air or flowing gas (O 2 , N 2 , or Ar), growth of intermetallic compounds from metallic flux or salt is more challenging because most intermetallics tend to oxidize in air and some are moisture sensitive, volatile, and/or poisonous.…”

Section: Introductionmentioning

confidence: 99%

Flux growth utilizing the reaction between flux and crucible

Yan

2015

Journal of Crystal Growth

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Flux growth involves dissolving the components of the target compound in an appropriate flux at high temperatures and then crystallizing under supersaturation controlled by cooling or evaporating the flux. A refractory crucible is generally used to contain the high temperature melt. The reaction between the melt and crucible materials can modify the composition of the melt, which typically results in growth failure, or contaminates the crystals. Thus one principle in designing a flux growth is to select suitable flux and crucible materials thus to avoid any reaction between them. In this paper, we review two cases of flux growth in which the reaction between flux and Al2O3 crucible tunes the oxygen content in the melt and helps the crystallization of desired compositions. For the case of La5Pb3O, Al2O3 crucible oxidizes La to form a passivating La2O3 layer which not only prevents further oxidization of La in the melt but also provides [O] to the melt. For the case of La0.4Na0.6Fe2As2, it is believed that the Al2O3 crucible reacts with NaAsO2 and the reaction consumes oxygen in the melt thus maintaining an oxygen-free environment.

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Materials discovery by crystal growth: Lanthanide metal containing oxides of the platinum group metals (Ru, Os, Ir, Rh, Pd, Pt) from molten alkali metal hydroxides

Cited by 67 publications

References 142 publications

Crystal growth of K2UO4 and Na4UO5 using hydroxide fluxes

Crystal growth of K2UO4 and Na4UO5 using hydroxide fluxes

In situ studies of a platform for metastable inorganic crystal growth and materials discovery

Flux growth utilizing the reaction between flux and crucible

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