Particle Swarm Predictions of a SrB₈ Monolayer with 12-Fold Metal Coordination

Abstract

Materials containing planar hypercoordinate motifs greatly enriched the fundamental understanding of chemical bonding. Herein, by means of first-principles calculations combined with global minimum search, we discovered the two-dimensional (2D) SrB 8 monolayer, which has the highest planar coordination number ( 12) reported so far in extended periodic materials. In the SrB 8 monolayer, bridged B 8 units are forming the boron monolayer consisting of B 12 rings, and the Sr atoms are embedded at the center of these B 12 rings, leading to the Sr@B 12 motifs. The SrB 8 monolayer has good thermodynamic, kinetic, and thermal stabilities, which is attributed to the geometry fit between the size of the Sr atom and cavity of the B 12 rings, as well as the electron transfer from Sr atoms to electron-deficient boron network. Placing the SrB 8 monolayer on the Ag(001) surface shows good commensurability of the lattices and small vertical structure undulations, suggesting the feasibility of its experimental realization by epitaxial growth. Potential applications of the SrB 8 monolayer on metal ions storage (for Li, Na, and K) are explored.

Stabilized Nitrogen Framework Anions in the Ga–N System

“…The structural prediction is based on a global minimum search of the free energy surfaces calculated via ab initio density functional theory (DFT) total-energy calculation and through the particle swarm optimization algorithm implemented in the CALYPSO method. − The key feature of this methodology is its capability of predicting the ground-state stable structures of materials with only the knowledge of chemical composition under ambient or given external conditions (e.g., pressure). − The candidate structure was predicted at 0, 20, 40, 60, and 80 GPa using a simulation cell comprising two and four formula units. The ab initio structural relaxations and electronic properties were examined in the framework of DFT as implemented in the Vienna ab initio simulation package (VASP) code .…”

TMB12: a newly designed 2D transition-metal boride for spintronics and electrochemical catalyst applications

“…Despite the progress, people's efforts on 2D hypercoordinate metal boride monolayers with excellent magnetic properties are still limited. Inspired by the discovery of various M-centered borometallic molecular wheels, such as FeB 8 − , FeB 9 − , CoB 8 − , RuB 9 − , RhB 9 − , IrB 9 − , TaB 10 − , SrB 12 − , etc ., 27,32 one would wonder if there exist other hypercoordinate metal boride monolayers formed by the swarm of M©B n wheels that can be stabilized in 2D space and possess exceptional magnetic properties. In this work, through spin-polarized ab initio calculations, we predicted a set of TMB 12 (TM = Ti, V, Cr, Mn, Fe; B = boron) monolayers by the condensation of TM©B 8 and B 4 units.…”

Robust Sandwiched B/TM/B Structures by Metal Intercalating into Bilayer Borophene Leading to Excellent Hydrogen Evolution Reaction

“…Except for charge transferring from the metal substrate, regulation like metal doping and intercalation can be also pervaded ways to afford external charge required for the stability of borophene. Several freestanding metal-borophene networks including the second and third main group elements (Mg, [48] Ca, [48] Sr, [49] Al, [50][51][52][53] Ga, [54] In [54] ), as well as partial transition metal elements (Sc, [48,55] Ti, [48,[56][57][58] V, [56] Cr, [56] Mn, [56,59,60] Fe, [61,62] Y, [48] Zr, [57,58] Mo, [63] Hf, [57,58] W, [64] Ir [65] ), have been reported. Among the transition metal borides (TMB) coexist various attractive characteristics, especially, strong mechanical properties and stability.…”

“…Therefore, one might raise the question that are there other 2D metal-borophene networks except for those reported previously? [48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65] What is the most stable structure? Especially, the potential catalytic application of metal-borophene networks is an interesting issue, which may offer more opportunities to search for the next generation of catalytic platforms.…”