Alignment of Amorphous Iron Oxide Clusters: A Non‐Classical Mechanism for Magnetite Formation

Sun, Shengtong; Gebauer, Denis; Cölfen, Helmut

doi:10.1002/anie.201610275

Cited by 55 publications

(50 citation statements)

References 48 publications

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“…While our reaction conditions are significantly different from those used by organisms during biomineralization, our results demonstrate that this non‐classical pathway is a possible route for the precipitation of aragonite. The similarity of the particle attachment mechanisms observed in forming biominerals and in vitro suggests that a similar mechanism is indeed possible in biogenic systems. Further work is required to confirm this hypothesis.…”

Section: Figurementioning

confidence: 80%

Solid‐State Transformation of Amorphous Calcium Carbonate to Aragonite Captured by CryoTEM

2017

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Early-stage reaction mechanisms for aragonitepromoting systems are relatively unknown compared to the more thermodynamically stable calcium carbonate polymorph, calcite.U sing cryoTEM and SEM, the early reaction stages taking place during aragonite formation were identified in ah ighly supersaturated solution using an alcohol-water solvent, and an overall particle attachment growth mechanism was described for the system. In vitro evidence is provided for the solid-state transformation of amorphous calcium carbonate to aragonite,d emonstrating the co-existence of both amorphous and crystalline material within the same aragonite needle.T his supports non-classical formation of aragonite within both asynthetic and biological context.

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Section: Figurementioning

confidence: 80%

Solid‐State Transformation of Amorphous Calcium Carbonate to Aragonite Captured by CryoTEM

2017

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“…S5c). This pre-aligned clusters were deemed as direct precursors of iron crystal and the alignment was hypothesized based on the anisotropic structural features within the short-range structure of the clusters [31]. Furthermore, the crystalline nature and the surface state of the ex-situ products were investigated via XRD and FT-IR.…”

Section: Ex-situ Chemical Kinetic Process Exploration Of Fe 3 O 4 Sphmentioning

confidence: 99%

“…Furthermore, understanding of the formation mechanism is an essential prerequisite for establishing the scope of synthesis of Fe 3 O 4 spheres for broad applications. In previous studies [24][25][26][27][28][29][30][31][32], polyol has been widely employed as both solvent and reductant while either PAA or Na 3 Cit is used as stabilizer. Cheng et al [14] reported that the formation of Fe 3 O 4 spheres depended on the balance of surface tension and electrostatic repelling forces of citrate molecules on the surface of nanocrystals.…”

Section: Introductionmentioning

confidence: 99%

Monodisperse Fe3O4 spheres: Large-scale controlled synthesis in the absence of surfactants and chemical kinetic process

Wang

Ali

et al. 2019

Sci. China Mater.

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Fe 3 O 4 has attracted tremendous interest in vast areas of biomedicine and catalysis as well as environment engineering. However, it is highly desired to fully understand the chemical kinetic process and propose a general, surfactantfree, large-scale synthesis approach for Fe 3 O 4 spheres. Herein, we developed a facile scalable solvothermal method in the absence of surfactants to produce Fe 3 O 4 spheres with the yield of 5.1 g, which present tunable sizes from 107 to 450 nm by modulated molar ratio of Fe 3+ /COO − in the solution. Particularly, it is observed that the reactants undergo a redox process, composed of a precipitation-dissolution equilibrium combined with a coordination reaction (termed as RPC), to the final product based on the LaMer model. It is worth noting that the generation of di-carboxyl group and its coordination with iron cations determine the formation of Fe 3 O 4 spheres. This work not only offers a strategy to precisely tailor the particle size in scalable synthesis process, but also gives the insight on the role of dihydric alcohol in the formation mechanism of Fe 3 O 4 spheres in the absence of surfactants.

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“…However, with a suitable application of ionic and polymeric additives, amorphous particles can be colloidally stabilized, also regulating the kinetics of crystallization. For instance, the nucleation of amorphous phases in the presence of certain polymers and stabilizing shells limits particle growth and coalescence ,,. Alternatively certain small molecules and ions applied as isomorphic substituents impede the phase transformation of amorphous intermediates .…”

Section: On the Nature Of Materials Precursorsmentioning

confidence: 99%

From Solute, Fluidic and Particulate Precursors to Complex Organizations of Matter

Rao

Cölfen

2018

The Chemical Record

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The organization of matter from its constitutive units recruits intermediate states with distinctive degrees of self-association and molecular order. Existing as clusters, droplets, gels as well as amorphous and crystalline nanoparticles, these precursor forms have fundamental contributions towards the composition and structure of inorganic and organic architectures. In this personal account, we show that the transitions from atoms, molecules or ionic species to superstructures of higher order are intertwined with the interfaces and interactions of precursor and intermediate states. Structural organizations distributed across different length scales are explained by the multistep nature of nucleation and crystallization, which can be guided towards functional hybrid materials by the strategic application of additives, templates and reaction environments. Thus, the non-classical pathways for material formation and growth offer conceptual frameworks for elucidating, inducing and directing fascinating material organizations of biogenic and synthetic origins.

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Alignment of Amorphous Iron Oxide Clusters: A Non‐Classical Mechanism for Magnetite Formation

Cited by 55 publications

References 48 publications

Solid‐State Transformation of Amorphous Calcium Carbonate to Aragonite Captured by CryoTEM

Solid‐State Transformation of Amorphous Calcium Carbonate to Aragonite Captured by CryoTEM

Monodisperse Fe3O4 spheres: Large-scale controlled synthesis in the absence of surfactants and chemical kinetic process

From Solute, Fluidic and Particulate Precursors to Complex Organizations of Matter

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