1. O RGANIC S TRUCTURES Ways to write complex molecules

2. S OME REMINDERS … Carbon compounds will form (almost always) four bonds They can several possible combinations with other atoms If all the bonds are single: (four sigma bonds) they have sp 3 hybidization, 109.5 o, tetrahedral If there are two singles and one double (three sigma’s and one pi): they have sp 2 hridization, 120 o, trigonal planar If there are two doubles (two sigma and two pi bonds): they have sp hybrization, 180 o, linear O=C=O C O H H C H H H H

3. C ARBON S TRUCTURES Carbon can form long chains: C C C C C C C C C The chains can continue for millions of carbon atoms The bond angles are, in the simplest case, 109.5 o

4. C ARBON S TRUCTURES C C C C C C C C C In the simplest case… Each carbon is surrounded by two hydrogens The end carbons have an extra hydrogen HH HHHHHHHH HHHHHH HH H H So the formula for the simplest carbon compounds is C n H 2n+2

5. D RAWING C ARBON S TRUCTURES …1 C C C C C C C C C HH HHHHHHHH HHHHHH HH H H Carbon structures can be written many ways… Often, the bonds will be written at right angles… CCCCCCCCC HH HHHHHHHH HHHHHH H H H H Sometimes, the carbons and hydrogens will be written together… CH 3 CH 2 CH 3 Repeated carbons and hydrogens can be compressed even more… CH 3 (CH 2 ) 7 CH 3

6. D RAWING C ARBON S TRUCTURES …2 C C C C C C C C C Hydrogen may often be left out… Or linear… CCCCCCCCC Other important elements, like oxygen or nitrogen can be included… Either angular… C C C C C C NH 2 OH CCCCCC NH 2 Notice that the hydrogen bonded to the other elements is included H H H H

7. D RAWING C ARBON S TRUCTURES …3 Carbon may be left out, showing only the carbon- carbon bonds… C 9 H 20 Double or triple bonds are straight-forward… C 9 H 18 Non-carbon or hydrogen groups may be added… OH NH 2 C 6 H 20 NH 2 OH