Caesium in high oxidation states and as a p-block element

Miao, Maosheng

doi:10.1038/nchem.1754

Cited by 187 publications

(191 citation statements)

References 46 publications

Supporting

Mentioning

184

Contrasting

Unclassified

Order By: Relevance

“…To compare the stability of Li n Cs m compounds, we constructed a convex hull from the calculated enthalpies of the most stable structures for each composition. The enthalpy of formation per atom was calculated using the following formula: 14,20,27). At a given pressure, the compounds located on the convex hull are stable against the decomposition into any other compositions, whereas the compounds that are above the convex hull are not energetically stable and will decompose into the compounds located on the hull.…”

Section: Resultsmentioning

confidence: 99%

“…The ICOHP of Cs-Cs and Cs-Li can be as large as 2.042 and 1.539 eV per pair, respectively, in Li 5 Cs. In comparison, the ICOHP of Cs-F in CsF 3 at 100 GPa is 1.787 eV per pair 14 . The large variation of Li 3 Cs from the general trend of ICOHPs is most likely caused by the fact that Cs atoms are enclosed in Li icosahedra, and therefore, Cs-Cs bonding is weakened.…”

Section: Articlementioning

confidence: 99%

“…In a recent study using first principles calculations, we demonstrated that the energy of the Cs 5p orbitals may become higher than that of the F 2p under pressure, and thus, Cs and F can form stable CsF n (n41) compounds 14 . The CsF n units are stable in the form of neutral or ionic molecules with bonding features and properties that resemble the isoelectronic XeF n .…”

mentioning

confidence: 99%

See 2 more Smart Citations

Pressure-stabilized lithium caesides with caesium anions beyond the −1 state

Botana

Miao

2014

Nat Commun

Self Cite

View full text Add to dashboard Cite

Main group elements usually assume a typical oxidation state while forming compounds with other species. Group I elements are usually in the þ 1 state in inorganic materials. Our recent work reveals that pressure may make the inner shell 5p electrons of Cs reactive, causing Cs to expand beyond the þ 1 oxidation state. Here we predict that pressure can cause large electron transfer from light alkali metals such as Li to Cs, causing Cs to become anionic with a formal charge much beyond À 1. Although Li and Cs only form alloys at ambient conditions, we demonstrate that these metals form stable intermetallic Li n Cs (n ¼ 1-5) compounds under pressures higher than 100 GPa. Once formed, these compounds exhibit interesting structural features, including capped cuboids and dimerized icosahedra. Finally, we explore the possibility of superconductivity in metastable LiCs and discuss the effect of the unusual anionic state of Cs on the transition temperature.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Articlementioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Pressure-stabilized lithium caesides with caesium anions beyond the −1 state

Botana

Miao

2014

Nat Commun

Self Cite

View full text Add to dashboard Cite

show abstract

“…The search for low-energy crystalline structures of La-H was performed using particle swarm optimization methodology implemented in the CALYPSO code (31,32). This method has been applied successfully to a wide range of crystalline systems ranging from elemental solids to binary and ternary compounds (33)(34)(35) and has proven to be a powerful tool for predicting crystal structures at high pressures (36)(37)(38)(39). Structure searches were performed in the pressure range of 150-300 GPa using models consisting of 1-4 formula units.…”

mentioning

confidence: 99%

Potential high- T _c superconducting lanthanum and yttrium hydrides at high pressure

Liu

Naumov

Hoffmann

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

711

463

View full text Add to dashboard Cite

A systematic structure search in the La-H and Y-H systems under pressure reveals some hydrogen-rich structures with intriguing electronic properties. For example, LaH 10 is found to adopt a sodalite-like face-centered cubic (fcc) structure, stable above 200 GPa, and LaH 8 a C2/m space group structure. Phonon calculations indicate both are dynamically stable; electron phonon calculations coupled to Bardeen-Cooper-Schrieffer (BCS) arguments indicate they might be high-T c superconductors. In particular, the superconducting transition temperature T c calculated for LaH 10 is 274-286 K at 210 GPa. Similar calculations for the Y-H system predict stability of the sodalite-like fcc YH 10 and a T c above room temperature, reaching 305-326 K at 250 GPa. The study suggests that dense hydrides consisting of these and related hydrogen polyhedral networks may represent new classes of potential very hightemperature superconductors.high pressure | superconductivity | hydrides | structure search E xtending his original predictions of very high-temperature superconductivity of high-pressure metallic hydrogen (1), Ashcroft later proposed that hydrogen-rich materials containing main group elements might exhibit superconductivity at lower pressures, as the hydrogen in these structures may be considered "chemically precompressed" (2). These proposals, which were based on the Bardeen-Cooper-Schrieffer (BCS) (3) phononmediated theory of superconductivity, have motivated many theoretical and experimental efforts in the search for hightemperature superconductivity in hydrides at elevated pressures (4-10). Theory has predicted the stability of a variety of dense hydride structures for which BCS arguments give superconducting transition temperatures, T c s, that are very high (11)(12)(13)(14)(15)(16)(17)(18).In recent times, compression of hydrogen sulfides has provided a new incentive in hydride superconductivity, one in which theory played an important role. First, theoretical calculations predicted H 2 S to have a T c of ∼80 K at pressures above 100 GPa (19). Compression of H 2 S led to the striking discovery of a superconducting material with a T c of 203 K at 200 GPa (20). Moreover, the critical temperature exhibits a pronounced isotope shift consistent with BCS theory. It was proposed that the superconducting phase is not stoichiometric H 2 S but SH 3 , with a calculated T c of 194 K at 200 GPa including anharmonic effects (21,22). A subsequent experiment (23) suggested that the superconducting phase is cubic SH 3 , in agreement with a theoretical study that gave T c = 204 K within the harmonic approximation (24). Compression of another hydride, PH 3 , was reported to reach a T c of ∼100 K at high pressures (25). Subsequent theoretical calculations predicted possible structures and calculated T c s close to the experimental results (26-28). The experimental picture for these materials remains not entirely clear, and the synthesis of the superconducting phases, which has been reproduced for hydrogen sulfide, is path-dependent (23).Th...

show abstract

“…With the help of crystal structure prediction, chemical reactions of Hg + F 2 and Cs + F 2 at HP conditions were predicted with the formation of novel compounds with unusual stoichiometries. 186,187 Hg in HgF 4 compound was found in an unusual high oxidation state of 5d 8 , while…”

Section: Chemical Reactions At Hpmentioning

confidence: 99%

Perspective: Crystal structure prediction at high pressures

Wang

2014

The Journal of Chemical Physics

156

124

View full text Add to dashboard Cite

Crystal structure prediction at high pressures unbiased by any prior known structure information has recently become a topic of considerable interest. We here present a short overview of recently developed structure prediction methods and propose current challenges for crystal structure prediction. We focus on first-principles crystal structure prediction at high pressures, paying particular attention to novel high pressure structures uncovered by efficient structure prediction methods. Finally, a brief perspective on the outstanding issues that remain to be solved and some directions for future structure prediction researches at high pressure are presented and discussed. © 2014 AIP Publishing LLC.

show abstract

Caesium in high oxidation states and as a p-block element

Cited by 187 publications

References 46 publications

Pressure-stabilized lithium caesides with caesium anions beyond the −1 state

Pressure-stabilized lithium caesides with caesium anions beyond the −1 state

Potential high- T _c superconducting lanthanum and yttrium hydrides at high pressure

Perspective: Crystal structure prediction at high pressures

Contact Info

Product

Resources

About

Caesium in high oxidation states and as a p-block element

Cited by 187 publications

References 46 publications

Pressure-stabilized lithium caesides with caesium anions beyond the −1 state

Pressure-stabilized lithium caesides with caesium anions beyond the −1 state

Potential high- T c superconducting lanthanum and yttrium hydrides at high pressure

Perspective: Crystal structure prediction at high pressures

Contact Info

Product

Resources

About

Potential high- T _c superconducting lanthanum and yttrium hydrides at high pressure