Sertraline is a white crystalline powder with chemical formula C17H17NCl2. Besides depression, sertraline can be used in treatment of panic disorder, social phobia, and obsessive-compulsive disorder. The most common side effects include nausea, diarrhea, insomnia, drowsiness, and dry mouth.

Chemical structure:

    H      H  H H  H H  H   H
     \    /    \|  |/    \ /
      C--C  H   C--C      C--H
    //    \\ \ /    \    /
Cl--C      C--C      C--N
     \    /    \    / \  \
      C==C  H   C==C   H  H
     /    \  \ /    \
    Cl     H  C      C--H
              \\    //
                C--C
                |  |
                H  H

Sources:
http://www.rxlist.com/cgi/generic/sertral.htm
http://www.psyweb.com/Drughtm/sertra.html