CHEMISTRY IN ITALY DURING LATE 18TH AND 19TH CENTURIES Ignazio Renato Bellobono, CSci, CChem, FRSC LASA, Department of Physics, University of Milan. e-mail add ress : i.bell obon o@ti scali.it LASA, Dept.Dept. ofPhysics, Physics, University of Milan The birth of Electrochemistry Luigi Galvani, Alessandro Volta, and Luigi Valentino Brugnatelli From Chemistry to Radiochemistry The birth of Chemistry and Periodic Table Amedeo Avogadro and Stanislao Cannizzaro Contributions to Organic Chemistry LASA, Dept.Dept. ofPhysics, Physics, University of Milan 1737 At the Faculty of Medicine of the Bologna University, the first chair of Chemistry is establishedestablished,,andandassigned to Jacopo Bartolomeo BECCARI (1692-1766). He studied phosphorescence and the action of light on silver halides 1776 In some marshes of the Lago Maggiore, near AngeraAngera,, Alessandro VOLTA ((17451745--18271827),),hi gh school teacher of physics in Como, individuates a flammable gas, which he calls aria infiammabile. Methane is thus discovereddiscovered.. Two years laterlater,,heheis assignedassigned,,asas professor of experimental phihysicscs,,toto the UiUniversi ty of PiPavia LASA, DtDept. of PhPhys icscs,, University of Milan 1778 In aletter a letter to Horace Bénédict de Saussure, aaSwissSwiss naturalist, VOLTA introduces, beneath that of electrical capacitycapacity,, the fundamental concept of tensione elettrica (electrical tension), exactly the name that CITCE recommended for the difference of potential in an electrochemical cell. 17901790--17911791 VOLTA anticipatesanticipates,,bybyabout 10 yearsyears,,thethe GAYGAY--LUSSACLUSSAC linear de ppyendency of gas volume on tem pp,erature, at constant pressurepressure,,andandafew a fewyears later ((17951795)) anticipatesanticipates,,byby about 6years 6 years,,thethe soso--calledcalled John Dalton’s rules ((18011801))ononvapour pressure LASA, Dept.Dept. ofPhysics, Physics, University of Milan 1790 Luigi GALVANI (1737 (1737——17981798),),a physiologist and anatomist, anatomist, while applying an electrical stimulus to a sectioned frog, observedobserved,,byby touching the crural nervesnerves,,thatthatconvulsive movements occurred along its limbs, and attributed this phenomenon to animal electricity ,,asaswell as to a connection between electricity and life. VOLTA’s controversy on this point of view is well knownknown;;butbut finaaylly he recognised the ppoioneering vaaulue of Galv ani ‘s experimentsexperiments,,whenwhenhis successful studies on the connection between chemical energy and electricity lead to the discovery, discovery,aafewfewyears later ((17991799--18001800),), of the pila di Volta . Phenomena occurring in this device to convert chemical energyyintinto electrical energy have been also named galvanism ((galvanicgalvaniccells) cells) LASA, Dept.Dept. ofPhysics, Physics, University of Milan 1792 Luigi Valentino BRUGNATELLI (1761 (1761--18181818),), professor at the University of Pavia since 1796, edits Annali di ChimicaChimica.. Some years later ((startingstarting from 18001800),), by using the pila di Volta (electrochemical cell able to convert chemical energy into electrical energyenergy),),he studies the reverse phenomenon (electrolysis, that is use of electricity to produce chemicalschemicals)) 1799 VOLTA, coming back from Pavia to Como (because (because the UiUniversit yyoof PiPaviaawaswas suppressed by the AtiAustrian rulersrulers,,andandbonapartist professors were banishedbanished))waswas studying, around these years, what we now call VOLTA’s effect. LASA, Dept.Dept. ofPhysics, Physics, University of Milan When putting into contact different metals, metals,duedueto different energy lllevelssoof the irrconcondtiduction bdbandss,,anane ltlectron flow takes placeplace.. In those timestimes,,anywayanyway,,thisthis quantum mechanical explanation was far from being reached. reached.TowardsTowards the end of 17991799,, howeverowever,,VOLTAVOLTA’’’s distinction between dry metals,,forforwhich the VOLTA’s effect appliesapplies,,andand humid metltals,,wwhenen,, iiin the presence of condtiducting saltssororac id solutionssolutions,,aamoremore remarkable flow of electricity occurredoccurred,, was made clearr.. For the first time in the history of physics and chemistrychemistry,,conversionconversion of what we call chemical energy into electrical energy was clearly shownshown,,bybyadevice a device,,whichwhichVOLTA himself called pila (alternate and vertical piling up of two metals, put in mutual contact by an ionically conducting solution or medium). LASA, Dept.Dept. ofPhysics, Physics, University of Millan On March 20th, 1800, a communication was sent by VOLTA to Sir Joseph Banks, Banks,presidentpresident of the Royal Society, by which he announced to the scientific community the invention of his electromotive apparatus, apparatus, or artificial electric organ, as compared to the natural organs of some fishesfishes..TheThecommunication was published on Philosophical Transactions, with the title On the electricity excited by the mere contact of conducting substances of different kinds. After the Marengo’s defeat of the Austrian Army ((JuneJune14th 14th 1800), the first Consul Napoleon Bonaparte reopened the University of Pavia, and reinstated ,,bybyaspecific a specific decree, Alessandro VOLTA as professor of experimental physicsphysics,,andanddirector of the physics laboratorylaboratory.. LASA, Dept.Dept. ofPhysics, Physics, University of Milan High esteem and honours attributed by Napoleon to Volta, during the visit paid by VOLT A and BRUGNATELLI, to present VOLTA’s discovery at the Institut de France ((NovemberNovember 77thth1801) 1801)areare well known, known,andandhistorically documenteddocumented..VOLTAVOLTAwas designed as foreign member of the Institut and awarddded byytthe gold medldal,,witwith a lflife donationdonation,,asaswell as (in 18051805))byby the Légion d’Honneur d’Honneur award. In 1809 heewaswas didesigned as sena tor, and one year later countcount,,ofof the Regno d’Italia ,,createdcreated by Napoleon at his peak. In 18161816,,thetheVOLTA’s Opera Omnia were published in Florenceorence.. In 1819, VOLTA retire d tooprpritivate life, and died in his country house of Camnago (now (nowa fraction of Como, name d, iiin his honouronour,, Camnago Vlt)Volta) iiin MhMarch 55thth 18271827,,atatthe age of 82. 82. LASA, Dept.Dept. ofPhysics, Physics, University of Milan In 18221822,,fivefiveyears before the death of VOLTA, Amedeo AVOGADRO and Vittor io MICHELOTTI set up iiin TiTurinnaa series of fundamental experimentsexperiments,,toto develop the chilhemical theory o f pilail di VltVolta,,anand undtdiderstanding, iiin terms of chemical reactionsreactions,,thethe conversion of chemical into electrical energy, as well as the reverse process, which BRUGNATELLI had been pioneering in the early 19th century, that is the use of electrical energy, generated by VOLTA’s cells, cells,toto produce chemicalschemicals.. The loop was thus closed, closed,andandanew a new branch of ChemistryChemistry,, ELECTROCHEMISTRY,,waswas ready to tktakeeooff, iiin the name of VOLTA. VOLTA. LASA, Dept.Dept. ofPhysics, Physics, University of Milan An epistemologicalconsideration: consideration: Just one hundred years ((18991899--19001900))afterafter the date of VOLTA’s discovery of electrochemical cell, cell,ininaperiod a period dense of new discoveriesdiscoveries,,officially on December 1414th,th, 19001900,,atat 55pm,pm,in the Institute of Physics of Berlin UniversityUniversity,,MaxMaxPLANC K presented a lecturelecture,, Zur Theorie des Gesetzes der Energieverteilung in Normalspektrum, in which PLANCK, for the first time in the history of physicsphysics,,introducedintroduced the quantum,,aasmallsmall energy quantityy,,asas a “flformal assumption”,,oof which probblbably not even himself realised, realised,atat that timetime,,thethe tremendous itimportanceance.. LASA, Dept.Dept. ofPhysics, Physics, University of Milan A revolution was beginning in physics. physics.OnlyOnlyafew a fewyears beforebefore,,PLANCKPLANCK did not firmly believe in atomic theorytheory,, whichwhich,,ononthe contrary, contrary,hadhadbeen the base of all the chemistry of the 1919ththcentury, century,andand was strengthened by LdLudwig i BOLTZMANN, iiin hissstustudies on t heeseconsecond principle of thermodynamics. thermodynamics. PLANCK, effectivel y, durin g the two or three years which preceded the turn of the centurycentury,,disapproved the statistical and probabilistic approach of BOLTZMANN towards the second principle, principle,andandwas strongly polemical towards the whole atomic theory. theory. LASA, DtDept. of PhPhys icscs,, University of Milan FortunatelyFortunately,, just during the studies on the energy distribution in the spectrumspectrum,,PLANCK recognised his debt tdtowards BOLTZMANN,,proposeproposed toocacall BltBoltzmann’’’s constant the kkconstantconstant of his equation on energy dist rib uti onon,,wwhich was theesamesame as tha t of sttitiltatistical interpretation of the second principle by BotlzmannBotlzmann,,andand proposed in 1905 and 1906 the Nobel prize for the austrian scientist. scientist. LASA, DtDept. of PhPhys icscs,, University of Milan ButBut,,unfortunately, unfortunately,ititwas too latelate..BoltzmannBoltzmann,,feelingfeeling iltdisolated and unapprecitdiated, died iiin DiDuino, near TiTriest e, on September 19061906,,atatthe age of 62. 62.BoltzmannBoltzmannwas wrong iiin diidespising himself : heewaswas among theemosmost respected and admired physicists of the 1919ththcentury, century, and Planck, at