Theory of the Structure of Coherent Boundaries in ZrO2 Nanoparticles

Shevchenko, V. Ya.; Samoĭlovich, M. I.; Талис, А. Л.; Madison, A. E.

doi:10.1007/s10720-005-0077-x

Cited by 6 publications

(3 citation statements)

References 26 publications

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“…Most likely, such behavior of the pyro chlore-murataite system at the stage of crystallization is ensured by equal dimensions of murataite and pyro chlore nanoclusters, which lead to the formation of coherent structures with rational proportions of blocks cut out of parental structures. Phenomena of such kind are characteristic of the processes proceeding at the nanolevel (Shevchenko et al, 2001(Shevchenko et al, , 2004(Shevchenko et al, , 2005. From the crystal chemical point of view, the com pounds of the pyrochlore-murataite series are appar ently the most complex mixed oxides known to date.…”

Section: Discussionmentioning

confidence: 99%

Modular nature of the polysomatic pyrochlore-murataite series

et al. 2011

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Synthetic analogues of murataite, a very rare mineral-a complex oxide of REE, actinide, Ti, Fe, and other elements,-are of great interest as confinement matrices of radioactive wastes. They are produced by sintering (1200-1300°C) and melting (1500-1600°C) with subsequent crystallization of the melt. Four structural varieties of murataite distinguished by unit cell parameters have been established by TEM study. All these varieties are derivatives of the fluorite structure designated as murataite 3C, 5C, 7C, and 8C depend ing on repetition factor of a parameter of the fluorite subcell. The structural features of the synthetic murataite varieties are analyzed in this paper based on data obtained from high resolution electron micros copy, microdiffraction, and X ray refinement. The hypothesis of a modular structure of the members of poly somatic pyrochlore-murataite series has been confirmed. At the same time, the structural modules are zero dimensional rather than two dimensional as had previously been suggested. The combinations of zero dimensional modules in 3D space create the entire structural diversity of the polysomatic series.

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Section: Discussionmentioning

confidence: 99%

Modular nature of the polysomatic pyrochlore-murataite series

et al. 2011

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“…These structures can exist only in the nanoworld. Let us demonstrate how an icosahedral diamond-like nanoparticle (icosahedral diamond) can be constructed if it is treated as a nanostructure that has coherent boundaries and is composed of (insignificantly distorted) fragments of diamond and lonsdaleite (hexagonal diamond).In our earlier works [12][13][14], we developed the local approach. Within this approach, nanoparticles with coherent boundaries in the general case are assembled from a limited set of building blocks (geometrical structural complexes) determined by the fundamental (specifically, projective) manifolds and the principles of assembling are governed by the topological properties of a fiber space.…”

mentioning

confidence: 99%

“…In our earlier works [12][13][14], we developed the local approach. Within this approach, nanoparticles with coherent boundaries in the general case are assembled from a limited set of building blocks (geometrical structural complexes) determined by the fundamental (specifically, projective) manifolds and the principles of assembling are governed by the topological properties of a fiber space.…”

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confidence: 99%

Icosahedral diamond

Shevchenko

Madison

2006

Glass Phys Chem

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The structural inhomogeneity in combination with coherence is characteristic of structures of nanosized particles [1,2]. In this case, the chemical nature of substances (organic, inorganic, biological) appears to be immaterial, which suggests their mutual convergence [3]. The description (and chemical design) of spatially inhomogeneous and hybrid structures should be based on principles that are more general than those accepted in classical crystallography for describing macroscopic crystals by groups of isomorphic mapping of the infinite three-dimensional Euclidean space onto itself. The great diversity of "unusual" structures [4-10] inherent only in nanoobjects can be obtained by mapping (projecting) fragments of high-symmetry structures from different non-Euclidean (in the particular case, projective) spaces onto the three-dimensional Euclidean space E 3 or mapping these fragments onto manifolds embedded in the space E 3 . The concept of projection from one space onto another space with the loss of a part of information can be illustrated by the interrelation between genes and proteins, as well as between the description language and real structures, and is closely related to fundamental problems of "inorganic life" [11].Spatially inhomogeneous structures (centaurs) for which a local short-range order only insignificantly differs from a short-range order of one of the stable (metastable) structural modifications (macroscopic phases) of the material under investigation and different fragments are coherently joined into a unit should exist and be relatively stable in the nanoworld. The requirement for the absence of dangling bonds and substantial disturbances of the mutual coordination of atoms is particularly satisfied for atoms located at interfaces. This implies the absence of interfaces in their usual macroscopic meaning.Specifically, these requirements are met by tetrahedral (diamond-like) structures that, as a whole, have icosahedral symmetry. These structures can exist only in the nanoworld. Let us demonstrate how an icosahedral diamond-like nanoparticle (icosahedral diamond) can be constructed if it is treated as a nanostructure that has coherent boundaries and is composed of (insignificantly distorted) fragments of diamond and lonsdaleite (hexagonal diamond).In our earlier works [12][13][14], we developed the local approach. Within this approach, nanoparticles with coherent boundaries in the general case are assembled from a limited set of building blocks (geometrical structural complexes) determined by the fundamental (specifically, projective) manifolds and the principles of assembling are governed by the topological properties of a fiber space. The geometrical structural complexes of tetrahedrally coordinated structures were derived and it was shown that fragments of crystalline and quasicrystalline structures can be joined together into a unified nanostructure with coherent boundaries [12]. In [15], it was demonstrated that the local approach allows one to explain different types of icosahedral pack...

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