相关论文: New high-pressure form of boron is significantly i…
Oganov et al report a discovery of an ionic high-pressure /hitherto unknown phase of boron/. We show that this phase has been known since 1965, and it is a covalent material.
Boron is an element of fascinating chemical complexity. Controversies have shrouded this element since its discovery was announced in 1808: the new 'element' turned out to be a compound containing less than 60-70 percent of boron, and it…
A scientific discussion was recently raised on the interpretation of chemical bonding in the high pressure structure of Boron. Some remarks are given in this short commentary
Boron is a unique element, being the only element, all known polymorphs of which are superhard, and all of its crystal structures are distinct from any other element. The electron-deficient bonding in boron explains its remarkable…
This Comment points out a number of errors in the recent paper by Zarechnaya, Dubrovinskaia, Dubrovinsky, et al. (Phys. Rev. Lett. 102, 185501 (2009)). Results and conclusions presented by Zarechnaya et al. (2009) are either incorrect or…
Measurements of the hardness of a new high-pressure boron phase, orthorhombic {\gamma}-B28, are reported. According to the data obtained, {\gamma}-B28 has the highest hardness (~50 GPa) of all known crystalline modifications of boron.
Extreme pressures and temperatures are known to drastically affect the chemistry of iron oxides resulting in numerous compounds forming homologous series $n$FeO$\cdot m$Fe$_2$O$_3$ and the appearance of FeO$_2$. Here, based on the results…
Different phases of solid boron under high pressure are studied by first principles calculations. The $\alpha$-B$_{12}$ structure is found to be stable up to 270 GPa. Its semiconductor band gap (1.72 eV) decreases continuously to zero…
{\gamma}-B28 is a recently established high-pressure phase of boron. Its structure consists of icosahedral B12 clusters and B2 dumbbells in a NaCl-type arrangement (B2){\delta}+(B12){\delta}- and displays a significant charge transfer…
A selection of studies highlighting different manifestations of the strong interaction are presented. Many new results have become available this summer in the regimes of discovery, systematic survey, and precision measurements of bound…
The goal of this work is to report a systematic and balanced review of the progress made in recent years on the high-pressure behavior of iodates, a group of materials with multiple technological applications and peculiar behaviors under…
The complex crystal chemistry of elemental boron has led to numerous proposed structures with distinctive motifs as well as contradictory findings. Herein, evolutionary structure searches performed at 100 GPa have uncovered a series of…
We report the discovery of superconductivity in boron-doped diamond synthesized at high pressure (8-9 GPa) and temperature (2,500-2,800 K). Electrical resistivity, magnetic susceptibility, specific heat, and field-dependent resistance…
We report experimental and theoretical evidence that solid molecular ammonia becomes unstable at room temperature and high pressures and transforms into an ionic crystalline form. This material has been characterised in both hydrogenated…
Boron bulk crystals are marked by exceptional structural complexity and unusual related physical phenomena. Recent reports of hydrogenated $\alpha$-tetragonal and a new $\delta$-orthorhombic boron B$_{52}$ phase have raised many fundamental…
Two boron-rich chalcogenides B12S and B12Se isostructural to {\alpha}-rhombohedral boron were synthesized by chemical reaction of the elements at high-pressure - high-temperature conditions. The crystal structures and stoichiometries of…
Single crystals of novel orthorhombic (space group Pnnm) iron tetraboride FeB4 were synthesised at pressures above 8 GPa and high temperatures. Magnetic susceptibility measurements demonstrated bulk superconductivity below 2.9 K. The…
We report the discovery of a new class of molecular phases of solid nitrogen at high pressures and temperatures by Raman and infrared spectroscopy and powder x-ray diffraction. Unlike the molecular phases consisting of disk- and sphere-like…
The stability of different stoichiometric H$_n$Br ($n$=1-7) compounds under pressure are extensively studied using density functional theory calculations. Five new energetically stable stoichiometries of H$_2$Br, H$_3$Br, H$_4$Br, H$_5$Br,…
The existence of hadronic molecular-type hybrids consisting of a baryon and a meson is argued. Long-range interactions due to one-pion exchange is shown to be strong enough to produce a loosely bound state. Specific features of a molecular…