Turning Down the Heat: Design and Mechanism in Solid-State Synthesis

Stein, Andreas; Keller, Steven W.; Mallouk, Thomas E.

doi:10.1126/science.259.5101.1558

Cited by 556 publications

(308 citation statements)

References 67 publications

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“…However, thermodynamically metastable phases are routinely observed during materials synthesis, 27,28 and may possess superior properties for some applications as compared to those of their corresponding ground-states. If a metastable phase can be synthesized and kinetically retained, it can be a suitable candidate for use in functional devices.…”

Section: ■ Introductionmentioning

confidence: 99%

Thermodynamic Routes to Novel Metastable Nitrogen-Rich Nitrides

et al. 2017

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Compared to oxides, the nitrides are relatively unexplored, making them a promising chemical space for novel materials discovery. Of particular interest are nitrogen-rich nitrides, which often possess useful semiconducting properties for electronic and optoelectronic applications. However, such nitrogen-rich compounds are generally metastable, and the lack of a guiding theory for their synthesis has limited their exploration. Here, we review the remarkable metastability of observed nitrides, and examine the thermodynamics of how reactive nitrogen precursors can stabilize metastable nitrogen-rich compositions during materials synthesis. We map these thermodynamic strategies onto a predictive computational search, training a data-mined ionic substitution algorithm specifically for nitride discovery, which we combine with grand-canonical DFT-SCAN phase stability calculations to compute stabilizing nitrogen chemical potentials. We identify several new nitrogen-rich binary nitrides for experimental investigation, notably the transition metal nitrides Mn 3 N 4 , Cr 3 N 4 , V 3 N 4 , and Nb 3 N 5 , the main group nitride SbN, and the pernitrides FeN 2 , CrN 2 , and Cu 2 N 2 . By formulating rational thermodynamic routes to metastable compounds, we expand the search space for functional technological materials beyond equilibrium phases and compositions.

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Section: ■ Introductionmentioning

confidence: 99%

Thermodynamic Routes to Novel Metastable Nitrogen-Rich Nitrides

et al. 2017

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“…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)(2)(3)(4)(5)(6). The flux can be nonreactive or reactive; in the latter case the flux itself becomes incorporated into the product (7,8).…”

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.

133

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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“…Supramolecular framework has received increasing attention over the past decade, attributing to the structural diversity and potential applications in the field of molecular magnetism, biological redox active systems [1][2][3], selective separation and catalysis [4][5][6][7][8][9][10][11][12]. Among them, building units based on tridentate terpyridine-type ligands and octahedrally coordinated metal ions are of special interest as they reveal a variety of interesting structural and physicochemical properties [13].…”

Section: Discussionmentioning

confidence: 99%

Crystal structure of (2,2':6',2''-terpyridine)copper(II) diacetate monohydrate, [Cu(C15H11N3)](O2CCH3)2 · H2O

Zhang¹,

Fu²,

Ren³

et al. 2008

Zeitschrift Für Kristallographie - New Crystal Structures

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C 19H19CuN3O5, orthorhombic, Fdd2 (no. 43 DiscussionSupramolecular framework has received increasing attention over the past decade, attributing to the structural diversity and potential applications in the field of molecular magnetism, biological redox active systems [1][2][3], selective separation and catalysis [4][5][6][7][8][9][10][11][12]. Among them, building units based on tridentate terpyridine-type ligands and octahedrally coordinated metal ions are of special interest as they reveal a variety of interesting structural and physicochemical properties [13]. In the crystal structure of title compound, the Cu(II) ion is pentacoordinated by three N atoms of the tridentate chelating terpyridyl unit and two O atoms from two different acetate groups. The three d(Cu-N) fall in the range 1.961(2) -2.051(2) Å, and the two d(Cu-O) fall in the range 1.974(2) -2.111(3) Å. The N−Cu−N angles vary from 78.94(9)°to 158.33(9)°. These are comparable to literature values [14]. The coordination polyhedron is a distorted square pyramid with the O1 atom at the apical position. Through the intermolecular hydrogen bonds of the lattice water molecules and the oxygen atoms from two different acetate groups with O−H···O (2.699 Å, 166.09°; 2.819 Å, 146.42°) the adjacent mononuclear units are linked into a 1D chains running along [001]. Furthermore, the neighboring 1D chains are inter-linked to form the planes through the interchain C−H···O hydrogen bonds (3.301 Å, 139.46°) and the weak faceto-face p-p interactions of the terpyridine ring belonging to adjacent mono-nuclear units with distances of about 3.772 Å.

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Turning Down the Heat: Design and Mechanism in Solid-State Synthesis

Cited by 556 publications

References 67 publications

Thermodynamic Routes to Novel Metastable Nitrogen-Rich Nitrides

Thermodynamic Routes to Novel Metastable Nitrogen-Rich Nitrides

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

Crystal structure of (2,2':6',2''-terpyridine)copper(II) diacetate monohydrate, [Cu(C15H11N3)](O2CCH3)2 · H2O

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