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$8/$�� /LJDo}HV�4XtPLFDV � /,*$d®(6�48Ë0,&$6 3RU�TXr�HVWXGDU�OLJDo}HV�TXtPLFDV" 2�WLSR�GH�OLJDomR�LQWHUDW{PLFD�JHUDOPHQWH�H[SOLFD�D� SURSULHGDGH�GR�PDWHULDO� ([HPSOR� R�FDUERQR�SRGH�H[LVWLU�QD�IRUPD�GH�JUDILWH�TXH�p� PROH��HVFXUR�H�³JRUGXURVR´�H�QD�IRUPD�GH�GLDPDQWH�TXH�p� H[WUHPDPHQWH�GXUR�H�EULOKDQWH��(VVD�GLIHUHQoD�QDV� SURSULHGDGHV�p�GLUHWDPHQWH�DWULEXtGD�DR�WLSR�GH�OLJDomR� TXtPLFD�TXH�p�HQFRQWUDGD�QR�JUDILWH�H�QmR�QR�GLDPDQWH� 2 Os átomos de carbono na grafita também são unidos fortemente através de ligações covalentes, mas só dentro de um plano, diferentemente da rede 3D das ligações do diamante. Estes planos de átomos de carbono simplesmente empilham-se uns sobre os outros, sendo as forças de união entre os planos, muito fracas. Os planos de átomos de carbono podem então deslizar facilmente uns sobre os outros, e por isto a grafita é importante lubrificante! GRAFITADIAMANTE Ligação fraca Ligação forte 3 $�H[WUHPD�IUDJLOLGDGH�H� GXUH]D�GRV�PDWHULDLV� FHUkPLFRV�YHP�GD�QDWXUH]D� GDV�VXDV�OLJDo}HV�DWyPLFDV $V�HVWUXWXUDV�FULVWDOLQDV�� TXDQGR�SUHVHQWHV�VmR� H[WUHPDPHQWH�FRPSOH[DV ([HPSOR��2�y[LGR�GH�6LOtFLR� �6L2���SRGH�WHU�WUrV�IRUPDV� FULVWDOLQDV�GLVWLQWDV�� TXDUW]R��FULVWREDOLWH H� WULGLPLWH 4 2V�HOpWURQV�GH�YDOrQFLD��GR�~OWLPR�QtYHO��VmR�RV� TXH�SDUWLFLSDP�GDV�OLJDo}HV�TXtPLFDV� 2V�iWRPRV�EXVFDP�D�FRQILJXUDomR�PDLV�HVWiYHO� GRV�JDVHV�QREUHV��FRP���RX���HOpWURQV�QD� FDPDGD�GH�YDOrQFLD� 'HSHQGHQGR�GD�HQHUJLD�HQYROYLGD�QD�OLJDomR�HODV� SRGHP�VHU�GLYLGLGDV�HP )RUWHV� )UDFDV /,*$d®(6�48Ë0,&$6 � /LJDo}HV�IRUWHV� ,{QLFDV &RYDOHQWHV 0HWiOLFDV /LJDo}HV�IUDFDV� )RUoDV�GH�9DQ�GHU�ZDDOV�� 'LSROR�GLSROR 3RQWHV�GH�KLGURJrQLR 0DWHULDLV�FHUkPLFRV��OLJDo}HV�L{QLFDV�H�RX�FRYDOHQWHV &RPSRVWRV�RUJkQLFRV��/LJDomR�FRYDOHQWH������������������ /,*$d®(6�48Ë0,&$6 � &RQVWLWXLomR�GRV�0DWHULDLV 2V PDWHULDLV VmR FRQVWLWXtGRV SRU iWRPRV� TXH QR HVWDGR VyOLGR� VmR XQLGRV SRU OLJDo}HV TXtPLFDV H IRUoDV LQWHUPROHFXODUHV� (VVDV OLJDo}HV DIHWDP DV SURSULHGDGHV ItVLFDV H TXtPLFDV GRV PDWHULDLV� � Ligação Química 5(*5$�'2�2&7(72� ³Os átomos tendem a ganhar ou perder elétrons até que possuam uma camada externa que contenha um dubleto (H, He e Be) ou octeto de elétrons” 8 7,326�'(�/,*$d®(6 0HWiOLFD &RYDOHQWH ,{QLFD A eletronegatividade dos átomos é o que determina o tipo de ligação � *UXSRV����������������������������������������������������������������������������������������������� Estrutura de Lewis 10 (;(03/2��8WLOL]DQGR�RV�VtPERORV�GH�/HZLV 8WLOL]H RV VtPERORV GH /HZLV SDUD HVFUHYHU R GLDJUDPD GD UHDomR TXH RFRUUH HQWUH RV iWRPRV GH R[LJrQLR H GH VyGLR� IRUPDQGR RV tRQV 2�� H 1D� Primeiro vamos escrever os símbolos de Lewis para o Na e o O Faltam dois elétrons para completar o octeto do átomo de oxigênio. Cada átomo de Na pode fornecer apenas um. Então /LJDomR�,{QLFD 11 )25d$6�(�(1(5*,$6� '(�/,*$d2 12 )25d$�(�',67Æ1&,$�'(�/,*$d®(6 $�GLVWkQFLD�HQWUH���iWRPRV�p� GHWHUPLQDGD�SHOR�EDODQoR�GDV� IRUoDV�DWUDWLYDV�H�UHSXOVLYDV 4XDQWR�PDLV�SUy[LPRV�RV� iWRPRV�PDLRU�D�IRUoD�DWUDWLYD� HQWUH�HOHV�H�PDLRU�DLQGD�VmR�DV� IRUoDV�UHSXOVLYDV�GHYLGR�D� VREUHSRVLomR�GDV�FDPDGDV� PDLV�LQWHUQDV� 4XDQGR�D�VRPD�GDV�IRUoDV� DWUDWLYDV�H�UHSXOVLYDV�p�]HUR��RV� iWRPRV�HVWmR�QD�FKDPDGD� GLVWkQFLD�GH�HTXLOtEULR� 13 )25d$�'(�/,*$d®(6�(�5,*,'(= $�LQFOLQDomR�GD�FXUYD QR�SRQWR�GH� HTXLOtEULR�Gi�D�IRUoD�QHFHVViULD� SDUD�VHSDUDU�RV�iWRPRV�VHP� SURPRYHU�D�TXHEUD�GD�OLJDomR�� 2V�PDWHULDLV�TXH�DSUHVHQWDP�XPD� LQFOLQDomR�JUDQGH�VmR� FRQVLGHUDGRV�PDWHULDLV�UtJLGRV��� $R�FRQWUiULR��PDWHULDLV�TXH� DSUHVHQWDP�XPD�LQFOLQDomR�PDLV� WrQXH�VmR�EDVWDQWH�IOH[tYHLV�� $�ULJLGH]�H�D�IOH[LELOLGDGH�WDPEpP� HVWmR�DVVRFLDGDV�FRP�PyGXOR�GH� HODVWLFLGDGH��(��TXH�p�GHWHUPLQDGR� GD�LQFOLQDomR�GD�FXUYD�WHQVmR�[� GHIRUPDomR�REWLGD�QR�HQVDLR� PHFkQLFR�GH�UHVLVWrQFLD�j�WUDomR� Deformação medida (HH) Inclinação fornece Módulo E 14 $ GLVWkQFLD HQWUH RV GRLV Q~FOHRV GH KLGURJrQLR p FKDPDGD GH comprimento de ligação H D HQHUJLD QHFHVViULD SDUD VHSDUDU QRYDPHQWH RV iWRPRV GH KLGURJrQLR HQYROYLGRV QD OLJDomR HP iWRPRV QHXWURV p GH ��� N-�PRO H FRQKHFLGD FRPR energia de ligação. (Q HUJ LD� oo Distância internuclear o 8PD�PROpFXOD�p�PDLV�HVWiYHO� TXDQGR�VXD�HQHUJLD�p�PtQLPD $XPHQWR�GD�HQHUJLD�GHYLGR� D�UHSXOVmR�LQWHUQXFOHDU (1(5*,$�'(�/,*$d2 15 (1(5*,$�'(�/,*$d2 $OJXPDV YH]HV p PDLV FRQYHQLHQWH WUDEDOKDU FRP HQHUJLD �SRWHQFLDO� GR TXH IRUoDV GH OLJDo}HV� 0DWHPDWLFDPHQWH��HQHUJLD��(��H�IRUoD�GH�OLJDo}HV��)��HVWmR� UHODFLRQDGDV�SRU���( ³ )�GU $�PHQRU�HQHUJLD�p�R�SRQWR�GH�HTXLOtEULR Quanto mais profundo o poço de potencial maior a temperatura de fusão do material Devido as forcas de repulsão aumentarem muito mais com a aproximação dos átomos a curva não é simétrica. 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