RamCharitraMaurya InorganicChemistry Also of Interest BioinorganicChemistry. PhysiologicalFacets RamCharitraMaurya, ISBN----,e-ISBN---- MolecularSymmetryandGroupTheory. ApproachesinSpectroscopyandChemicalReactions R.C.Maurya,J.M.Mir, ISBN----,e-ISBN---- ChemistryoftheNon-Metals RalfSteudel, ISBN----,e-ISBN---- OrganoseleniumChemistry BrindabanC.Ranu,BubunBanerjee(Eds.), ISBN----,e-ISBN---- Ram Charitra Maurya Inorganic Chemistry Some New Facets Author Prof.Dr.RamCharitraMaurya Ph.D.,D.Sc,CChemFIC(India),CChemFRSC(UK) ProfessorofInorganicChemistry FormerHead,DepartmentofChemistryandPharmacy,and Dean,FacultyofScience RaniDurgavatiUniversity Jabalpur482001(M.P.),India [email protected] ISBN978-3-11-072725-8 e-ISBN(PDF)978-3-11-072728-9 e-ISBN(EPUB)978-3-11-072740-1 LibraryofCongressControlNumber:2020952731 BibliographicinformationpublishedbytheDeutscheNationalbibliothek TheDeutscheNationalbibliothekliststhispublicationintheDeutscheNationalbibliografie; detailedbibliographicdataareavailableontheInternetathttp://dnb.dnb.de. ©2021WalterdeGruyterGmbH,Berlin/Boston Coverimage:Piranka/Gettyimages Typesetting:IntegraSoftwareServicesPvt.Ltd. Printingandbinding:CPIbooksGmbH,Leck www.degruyter.com Dedicatedto Mywife Mrs.UshaRaniMaurya, whohasalwaysbeenasourceofinspirationforme throughoutmygrowth & Mysons,AshutoshandAnimesh;daughter,Abhilasha;andson-in-law,Adarsh for encouragement Preface Duringmylongjourneyofteachingspanofmorethan40yearsinthreedifferent universities at B.Tech., M.Sc., M.Phil. and Ph.D. levels, I had always realized the lack of textbooks in Inorganic Chemistry that covers most of the topics for in- depth teaching of the subject matters. Moreover, I was also in quest of reading materialsintheformofresearchpapers,reviewsandbooks,sothatcurriculumat Postgraduate, M.Phil. and Ph.D. coursework levels in any university of India and abroad toocanberevisedforupdatingmanpowersinChemistryformanifoldap- plications. The present book, entitled Inorganic Chemistry: Some New Facets, in- corporating 10chapters, is designed tomeet out the objectives mentioned above. Althoughmanymoretopicsarestillnotcoveredinthisbookonlybecauseoflook- ing over the too much bulk of the book, they will be given attention in its next volume. The book also aims to assist students in preparing for competitive examina- tions,viz.NET,GATE,SLETandDoctoralEntranceTest(DET)particularlyinIndia. Each chapter ends with different multiple choice, short answer and long answer questions, covering the topics discussed in the chapter to allow an opportunity to thestudentsfortheirself-evaluation. Incompletingabookofthisnature,oneaccumulatesgratefulnesstotheprevi- ousauthorsandeditorsofbooks,researchpapers,reviewsandmonographsonthe relevanttopics.Ihaveconsultedthesesourcesfreelyandborrowedtheirideasand viewswithnohesitationinpreparingthepresentmanuscript.Thesesourcesareac- knowledgedandlistedinbibliography,andIamhighlythankfultotheseauthors. Moreover,thepresentbookistheoutcomeofmyteachingofthesubjectformore than 40 years to several batches of Masters, M.Phil. and Ph.D. coursework students attheDepartmentofChemistry,AtarraP.G.College,Atarra(BundelkhandUniversity, Jhansi, U.P., India) and Rani Durgavati University, Jabalpur (M.P.), India. I have benefitedenormouslyfromtheresponse,questionsandcriticismsofmystudents. Looking over the problems of students inlearning thesubject, I have tried my besttopresentthesubjectwithastudent-friendlyapproach,thatis,expressingitin an interactive manner and in simple language with many illustrative examples. Moreover, the mathematical parts wherever required are given in details to make the subject easily understandable. Therefore, I hope that the book will serve as a textforM.Sc.,M.Phil.andPh.D.courseworkstudentsofChemistry. My endeavour will be amply rewarded if the book is found helpful to the stu- dentsandteachers.Despiteseriousattemptstokeepthetextfreeoferrors,itwould be presumptuous to hope that no error has crept in.Ishall be grateful to allthose who may care to send their criticism and suggestions for the improvement of the bookonmye-mailID([email protected]). https://doi.org/10.1515/9783110727289-202 VIII Preface The writing of this book was initiated in September 2018 at 4515 Wavertree Drive, Missouri City, Texas 77459, USA, during our stay with my daughter, Dr. Abhilasha,andson-in-law,Dr.Adarsh,forwhichtheydeservethanks. Lastbutnottheleast,Iamthankfultomywife,Mrs.UshaRaniMaurya,forher patient understanding of the ordeal which she had to undergo due to my almost one-sided attention during the completion of this challenging task. I am also in- debtedtomystudentsfortheirencouragementandcooperation. October2,2020 RamCharitraMaurya B-95,PriyadarshiniColony,DumnaAirportRoad, (Author) Jabalpur(M.P.),India Contents Preface VII ChapterI Valenceshellelectronpairrepulsion(VSEPR)theory:principles andapplications 1 1.1 Introduction 1 1.2 PostulatesofVSEPRtheory:SidgwickandPowell 1 1.3 RulesproposedbyGillespieandNyholm 1 1.3.1 Rule1.Spatialarrangementofelectronpairsaroundthecentral atomofagivenmolecule/ion 1 1.3.2 Rule2.Regularandirregulargeometry:presenceofhybrid orbitalscontainingbondpairsandlonepairs 3 1.3.3 Rule3.Effectofelectronegativity:repulsionsexertedbybond pairsdecreaseastheelectronegativityofthebondedatom increases 6 1.3.4 Rule4.Multiplebondsexertastrongerrepulsion 6 1.3.5 Rule5.Repulsionsbetweenelectronpairsinfilledshellsare largerthanthosebetweenelectronpairsinincomplete shells 6 1.4 ExceptionstotheVSEPRmodel,ligand–ligandrepulsionandthe ligandclosepackingmodel 8 1.5 ApplicationsofVSEPRtheory 10 1.6 ShortcomingsofVSEPRtheory 20 1.7 Bentrule 21 1.7.1 ConsistencyofBent’srulewithGillespie’sVSEPRmodel 23 Exercises 23 ChapterII Delocalizedπ-bondinginpolyatomicmolecules:molecularorbital approach 27 2.1 Localizedanddelocalizedbonds 27 2.1.1 Localizedσ-andπ-bonds 27 2.1.2 Delocalizedπ-bond(s) 27 2.2 Basicprinciplesofmolecularorbitaltheory:polyatomic moleculesorionsinvolvingdelocalizedπ-bonding 27 2.2.1 Variousstepsinvolvedinworkingoutdelocalizedπ-MOs 28 2.3 Delocalizedπ-bondinginnon-cyclicpolyatomicmolecules orions 29 2.3.1 Ozonemolecule(O ) 29 3 2.3.2 Nitrogendioxide(NO )molecule 32 2 X Contents 2.3.3 Nitriteion(NO −) 35 2 2.3.4 Delocalizedπ-bondinginhydrazoicacid 38 2.3.5 Delocalizedπ-bondinginhydrazoicion(N −) 41 3 2.3.6 Delocalizedπ-bondinginnitrateion(NO −) 44 3 2.3.7 Delocalizedπ-bondinginBF 48 3 2.3.8 Delocalizedπ-bondinginCu Omolecule 50 2 2.4 Delocalizedπ-bondingincyclicmolecules 53 2.4.1 Benzene(C H ) 54 6 6 2.4.2 Cyclopentadienylradical(C H ·) 56 5 5 2.5 Delocalizedπ-bondingincyclicions 59 2.5.1 3,4–Diketocyclobutenedianion(C O 2−) 60 4 4 2.5.2 Delocalizedπ-bondinginC O 2− 62 5 5 2.5.3 Delocalizedπ-bondinginC O 2− 64 6 6 Exercises 66 ChapterIII Chemistryofboraneandrelatedcompounds:structure,bonding andtopology 71 3.1 Introduction 71 3.2 Importanceofboranes 71 3.3 Classificationofboranes 71 3.3.1 Closo-boranes 71 3.3.2 Nido-boranes 72 3.3.3 Arachno-boranes 73 3.3.4 Hypho-boranes 73 3.3.5 Conjuncto-boranes 73 3.4 Nomenclatureofboranes 75 3.5 Propertiesofboranes 76 3.6 Metallaboranes/metalloboranesorboranecomplexes 76 3.7 Bondingandtopologyofboranes 79 3.7.1 Bondinginboranesandhigherboranes/boronclusters: molecularorbitalapproach 79 3.7.2 Molecularorbitalapproach 79 3.7.3 FormationofB–H–Bbond 80 3.7.4 FormationofB–B–Bbond 83 3.8 Topologyofboranes(Lipscomb’srule):styxfour-digitcodingof bondinginboranes 87 3.8.1 UtilityofLipscomb’srule 88 3.8.2 ValidityofLipscomb’srule 88 3.8.3 CalculationoftotalnumberofVEsandnumberofbondsin boraneswithoutmakinguseofLipscomb’srule 93