Related Experiment Video
Updated: Mar 22, 2026

Photochemical Oxidative Growth of Iridium Oxide Nanoparticles on CdSe@CdS Nanorods
Published on: February 11, 2016
Phase diagram and physical properties of iridium tetraboride from first principles
Xiaofeng Li1, Haiyan Wang, Jian Lv
1College of Physics and Electronic Information, Luoyang Normal College, Henan Luoyang, 471022, P. R. China. zlliu@163.com.
Abstract:
Using both the swarm-intelligence-based CALYPSO method and the multi-algorithm-collaborative (MAC) algorithm for crystal structure prediction, three unexpected new phases (P63/mmc, C2/m and Cmca) of IrB4 are predicted. The P63/mmc phase is the ground-state structure under ambient conditions, while C2/m and Cmca phases form at high pressure. The phase stabilities, mechanical and electronic properties of the three new phases of IrB4 are investigated systematically. We firstly found that pressure stimulates IrB4 to undergo phase transition twice, P63/mmc phase to C2/m phase at 29 GPa and C2/m phase to Cmca at 99 GPa. Strikingly, the three phases are both dynamically and mechanically stable under ambient conditions. The high bulk and shear moduli and low Poisson's ratio for the three phases in IrB4 make IrB4 a promising low-compressible material. Detailed analysis of density of states and electronic local functions reveals that the covalent bonding of Ir-B and B-B is responsible for their structural stability and high hardness. Finally, the high-pressure and high-temperature phase diagram of IrB4 is established, where the triple point of phase transition for P63/mmc-, C2/m- and Cmca-IrB4 is at 60 GPa and 1930 K.
More Related Videos
09:45Accessing Valuable Ligand Supports for Transition Metals: A Modified, Intermediate Scale Preparation of 1,2,3,4,5-Pentamethylcyclopentadiene
Published on: March 20, 2017
06:44From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding
Published on: March 24, 2018
Related Concept Videos
Phase Diagrams of Ternary Systems
Predicting Molecular Geometry
Properties of Transition Metals
Crystal Field Theory - Tetrahedral and Square Planar Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Phase Diagram
Phase Diagram