Penta-graphene

{{Chembox  | ImageFile = Penta-graphane.png | ImageSize = 250px | ImageCaption = Top view (top) and side view (bottom) of penta-graphane. Yellow and blue spheres show two types of carbon atoms, while red balls correspond to hydrogens.<ref name=stam/>  | IUPACName = | OtherNames = PG  | Section1 = {{Chembox Identifiers | CASNo = | PubChem = | SMILES = }} | Section2 = {{Chembox Properties | Formula = Cn | MolarMass = | Appearance = | Density = | MeltingPt = | BoilingPt = | Solubility = }} | Section3 = {{Chembox Hazards | MainHazards = | FlashPt = | AutoignitionPt = }} }}

'''Penta-graphene''' is a hypothetical carbon allotrope composed entirely of carbon pentagons and resembling the Cairo pentagonal tiling.<ref name="pnas"/> Penta-graphene was proposed in 2014 on the basis of analyses and simulations.<ref name="pnas"/> Further calculations predicted that it is unstable in its pure form,<ref name="pnas2"/> but can be stabilized by hydrogenation.<ref name=stam/> Due to its atomic configuration, penta-graphene has an unusually negative Poisson’s ratio and very high ideal strength believed to exceed that of a similar material, graphene.<ref name="pnas"/>

200px|thumb|left|Cairo pentagonal tiling

Penta-graphene contains both ''sp''2 and ''sp''3 hybridized carbon atoms. Contrary to graphene, which is a good conductor of electricity, penta-graphene is predicted to be an insulator with an indirect band gap of 4.1–4.3 eV. Its hydrogenated form is called penta-graphane. It has a diamond-like structure with ''sp''3 and no ''sp''2 bonds, and therefore a wider band gap (ca. 5.8 eV) than penta-graphene.<ref name=stam/> Chiral penta-graphene nanotubes have also been studied as metastable allotropes of carbon.<ref name="Atlahuice"/><ref name="pnas"/><ref name="PAvramon"/>

==References== <references>

<ref name="pnas">{{Cite journal | doi = 10.1073/pnas.1416591112| title = Penta-graphene: A new carbon allotrope| journal = Proceedings of the National Academy of Sciences| volume = 112| issue = 8| pages = 2372–2377| year = 2015| last1 = Zhang | first1 = S. | last2 = Zhou | first2 = J. | last3 = Wang | first3 = Q. | last4 = Chen | first4 = X. | last5 = Kawazoe | first5 = Y. | last6 = Jena | first6 = P. | pmc = 4345574| bibcode = 2015PNAS..112.2372Z | pmid=25646451| doi-access = free}}</ref> <ref name="pnas2">{{cite journal|doi= 10.1073/pnas.1520402112|title= Predicting experimentally stable allotropes: Instability of penta-graphene|journal= Proceedings of the National Academy of Sciences|pages= 15609–12|year= 2015|last1= Ewels|first1= Christopher P.|last2= Rocquefelte|first2= Xavier|last3= Kroto|first3= Harold W.|last4= Rayson|first4= Mark J.|last5= Briddon|first5= Patrick R.|last6= Heggie|first6= Malcolm I.|pmid=26644554|pmc=4697406|volume=112|issue= 51|bibcode= 2015PNAS..11215609E|doi-access= free}}</ref> <ref name=stam>{{cite journal|doi=10.1080/14686996.2016.1219970|arxiv=1511.06850|title=Studying the electronic and phononic structure of penta-graphane|journal=Science and Technology of Advanced Materials|volume=17|issue=1|pages=610–617|year=2016|last1=Einollahzadeh|first1=Hamideh|last2=Fazeli|first2=Seyed Mahdi|last3=Dariani|first3=Reza Sabet|pmc=5102001|pmid=27877907|bibcode=2016STAdM..17..610E}}</ref> <ref name="Atlahuice">{{cite journal|doi=10.1016/j.comptc.2017.03.019|title= Chiral penta-graphene nanotubes: Structure, bonding and electronic properties|journal= Computational and Theoretical Chemistry|pages= 70–75|year= 2017|last1= Quijano-Briones|first1= JJ.|last2= Fernandez_escamilla|first2= HN|last3= Tlahuice-Flores|first3= Alfredo.|volume=1108}}</ref> <ref name=PAvramon>{{cite journal|doi=10.1021/acs.jpclett.5b02309|title=Translation Symmetry Breakdown in Low-Dimensional Lattices of Pentagonal Rings|journal=J. Phys. Chem. Lett.|volume=6|issue=22|pages=4525–4531|year=2015|last1=Avramov|first1=P|last2=Demin|first2=V |last3=Luo|first3=M |pmid=26582476}}</ref>

</references>

==External links== * {{Cite journal | doi = 10.1016/j.nantod.2022.101501 | title = Research progress on penta-graphene and its related materials: Properties and applications | year = 2022 | last1 = Nazir | first1 = Muhammad Azhar | last2 = Hassan | first2 = Arzoo | last3 = Shen | first3 = Yiheng | last4 = Wang | first4 = Qian | journal = Nano Today | volume = 44 | article-number = 101501 | s2cid = 248767647 }}

Category:Graphene Category:Allotropes of carbon Category:Hypothetical chemical compounds