Crystal-Inspired Cellular Metamaterials and Triply Periodic Minimal Surfaces.

Triply periodic minimal surfaces (TPMSs) are found in many natural objects including butterfly wings, sea urchins, and biological membranes. They simultaneously have zero mean curvature at every point and a crystallographic group symmetry. A metamaterial can be created from such periodic surfaces or used as a reinforcement of a composite material.

High-Throughput Screening of 3D-Printed Architected Materials Inspired by Crystal Lattices: Procedure, Challenges, and Mechanical Properties.

The search for load-bearing, impact-resistant, and energy-absorbing cellular materials is of central interest in many fields including aerospace, automotive, civil, sports, packaging, and biomedical. In order to achieve the desired characteristic geometry and/or topology, a perspective approach may be used, such as utilization of atomic models as input data for 3D printing of macroscopic objects. In this paper, we suggest a new approach for the development of advanced cellular materials-crystallomorphic design based on selection of perspective crystal structures and modeling of their electron density distribution and utilization of isoelectronic surfaces as a generatrix for 3D-printed cellular materials.

AgBOX (X = Cl, Br, I) Heptaborate Family: Comprehensive Crystal Chemistry, Thermal Stability Trends, Topology, and Vibrational Anharmonicity.

Using glass crystallization and solid-state techniques, we were able to complete the family of salt-inclusion silver halide borates, AgBOX, by the X = Cl and I members. The new compounds are characterized by differential scanning calorimetry, single-crystal and high-temperature powder X-ray diffraction, optical spectroscopy, and density functional theory calculations. In all structures, the silver atoms exhibit strong anharmonicity of thermal vibrations, which could be modeled using Gram-Charlier expansion, and its asymmetry was characterized by the skewness vector.

Bridging the Salt-Inclusion and Open-Framework Structures: The Case of Acentric AgBOX (X = Br, I) Borate Halides.

An acentric borate family, AgBOX (X = Br, I), has been prepared by slow cooling stoichiometric melts in evacuated silica ampules. Their crystal structure is comprised of two porous interpenetrating frameworks and demonstrates a further development of the "salt-inclusion" architecture toward a "covalent-inclusion" structure. The (AgX) sublattice shows strong anharmonic vibrations.

The first silver bismuth borate, AgBiBO.

The first silver bismuth borate, AgBiBO (silver dibismuth pentaborate), has been prepared via glass crystallization in the AgO-BiO-BO system and characterized by single-crystal X-ray diffraction. Its structure is derived from that of centrosymmetric BiBO by ordered substitution of one Bi ion for Ag, which results in the disappearance of the mirror plane and inversion centre. Second harmonic generation (SHG) measurements confirm the acentric crystal structure.