Physical Review Letters · 2009 · 167 citations · 20 references
Natural SciencesMaterials SciencePhysicsCondensed Matter PhysicsCrystal StructureSolid State PhysicsAb Initio MethodsCrystal ChemistryElectronic Structure Of SolidsHigh-temperature MaterialsOptical Properties Of SolidsStrongly Correlated Electron SystemsAb Initio CalculationsBulk ModulusCompressibilityCovalent InteractionsHardnessHigh-pressure Phase BehaviorSingle-crystal DiffractionSingle-crystal X-ray Diffraction
An orthorhombic (space group Pnnm) boron phase was synthesized at pressures above 9 GPa and high temperature, and it was demonstrated to be stable at least up to 30 GPa. The structure, determined by single-crystal x-ray diffraction, consists of B12 icosahedra and B2 dumbbells. The charge density distribution obtained from experimental data and ab initio calculations suggests covalent chemical bonding in this phase. Strong covalent interatomic interactions explain the low compressibility value (bulk modulus is K300=227 GPa) and high hardness of high-pressure boron (Vickers hardness HV=58 GPa), after diamond the second hardest elemental material.
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Ionic high-pressure form of elemental boron
Artem R. Oganov, Jiuhua Chen, Carlo Gatti et al. · Nature · 2009 · 932 citations · Full text
Natural Sciences, Materials Engineering, Materials Science +7
M. I. Eremets, Viktor V. Struzhkin, Ho‐kwang Mao et al. · Science · 2001 · 318 citations