Carbon nitride frameworks and dense crystalline polymorphs

0463973 - ÚOCHB 2017 RIV US eng J - Journal Article
Pickard, C. J. - Salamat, A. - Bojdys, Michael J. - Needs, R. J. - McMillan, P. F.
Carbon nitride frameworks and dense crystalline polymorphs.
Physical Review B. Roč. 94, č. 9 (2016), č. článku 094104. ISSN 2469-9950. E-ISSN 2469-9969
Institutional support: RVO:61388963
Keywords : triazine-based frameworks * solid-state NMR * high pressure
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 3.836, year: 2016

We used ab initio random structure searching (AIRSS) to investigate polymorphism in C3N4 carbon nitride as a function of pressure. Our calculations reveal new framework structures, including a particularly stable chiral polymorph of space group P4(3)2(1)2 containing mixed sp(2) and sp(3) bonding, that we have produced experimentally and recovered to ambient conditions. As pressure is increased a sequence of structures with fully sp(3)-bonded C atoms and three-fold-coordinated N atoms is predicted, culminating in a dense Pnma phase above 250 GPa. Beyond 650 GPa we find that C3N4 becomes unstable to decomposition into diamond and pyrite-structured CN2.
Permanent Link: http://hdl.handle.net/11104/0263067