I written some code to generate all partens of $\ \mathrm{C_2H_5O}$, but theres some isomerisms need to be deleted.

Here's the raw output after `DeleteDuplicates`.

    del=DeleteDuplicates@raw
    del={{{"C",2}<->{"C",1},{"O",1}<->{"C",2},{"H",1}<->{"C",1},{"H",2}<->{"C",2},{"H",3}<->{"C",1},{"O",1}<->{"C",2},{"H",4}<->{"C",1}},{{"C",2}<->{"C",1},{"O",1}<->{"C",2},{"H",1}<->{"C",1},{"H",2}<->{"C",2},{"C",1}<->{"O",1},{"H",3}<->{"C",2},{"H",4}<->{"C",1}},{{"C",2}<->{"C",1},{"O",1}<->{"C",2},{"H",1}<->{"C",1},{"C",2}<->{"C",1},{"H",2}<->{"O",1},{"H",3}<->{"C",2},{"H",4}<->{"C",1}},{{"C",2}<->{"C",1},{"H",1}<->{"C",2},{"O",1}<->{"C",1},{"H",2}<->{"C",2},{"H",3}<->{"C",1},{"O",1}<->{"C",2},{"H",4}<->{"C",1}},{{"C",2}<->{"C",1},{"H",1}<->{"C",2},{"O",1}<->{"C",1},{"H",2}<->{"C",2},{"C",1}<->{"O",1},{"H",3}<->{"C",2},{"H",4}<->{"C",1}},{{"C",2}<->{"C",1},{"H",1}<->{"C",2},{"O",1}<->{"C",1},{"C",2}<->{"C",1},{"H",2}<->{"O",1},{"H",3}<->{"C",2},{"H",4}<->{"C",1}},{{"C",2}<->{"C",1},{"H",1}<->{"C",2},{"H",2}<->{"C",1},{"O",1}<->{"C",2},{"H",3}<->{"C",1},{"O",1}<->{"C",2},{"H",4}<->{"C",1}},{{"C",2}<->{"C",1},{"H",1}<->{"C",2},{"H",2}<->{"C",1},{"O",1}<->{"C",2},{"C",1}<->{"O",1},{"H",3}<->{"C",2},{"H",4}<->{"C",1}},{{"C",2}<->{"C",1},{"H",1}<->{"C",2},{"H",2}<->{"C",1},{"H",3}<->{"C",2},{"C",1}<->{"C",2},{"O",1}<->{"C",1},{"H",4}<->{"O",1}},{{"C",2}<->{"C",1},{"H",1}<->{"C",2},{"H",2}<->{"C",1},{"H",3}<->{"C",2},{"O",1}<->{"C",1},{"O",1}<->{"C",1},{"H",4}<->{"C",2}},{{"C",2}<->{"C",1},{"H",1}<->{"C",2},{"H",2}<->{"C",1},{"C",2}<->{"C",1},{"O",1}<->{"C",2},{"H",3}<->{"O",1},{"H",4}<->{"C",1}},{{"C",2}<->{"C",1},{"O",1}<->{"C",2},{"O",1}<->{"C",2},{"H",1}<->{"C",1},{"H",2}<->{"C",1},{"H",3}<->{"C",2},{"H",4}<->{"C",1}},{{"O",1}<->{"C",1},{"H",1}<->{"C",1},{"H",2}<->{"C",1},{"C",2}<->{"O",1},{"H",3}<->{"C",2},{"C",2}<->{"C",1},{"H",4}<->{"C",2}},{{"O",1}<->{"C",1},{"H",1}<->{"C",1},{"C",1}<->{"O",1},{"C",2}<->{"C",1},{"H",2}<->{"C",2},{"H",3}<->{"C",2},{"H",4}<->{"C",2}},{{"O",1}<->{"C",1},{"H",1}<->{"C",1},{"C",2}<->{"C",1},{"C",2}<->{"C",1},{"H",2}<->{"C",2},{"H",3}<->{"O",1},{"H",4}<->{"C",2}},{{"H",1}<->{"C",1},{"C",2}<->{"C",1},{"H",2}<->{"C",2},{"H",3}<->{"C",2},{"C",1}<->{"C",2},{"O",1}<->{"C",1},{"H",4}<->{"O",1}},{{"H",1}<->{"C",1},{"C",2}<->{"C",1},{"H",2}<->{"C",2},{"C",2}<->{"C",1},{"O",1}<->{"C",2},{"H",3}<->{"O",1},{"H",4}<->{"C",1}},{{"H",1}<->{"C",1},{"H",2}<->{"C",1},{"C",2}<->{"C",1},{"H",3}<->{"C",2},{"C",2}<->{"C",1},{"O",1}<->{"C",2},{"H",4}<->{"O",1}},{{"H",1}<->{"C",1},{"H",2}<->{"C",1},{"C",2}<->{"C",1},{"C",2}<->{"C",1},{"O",1}<->{"C",2},{"H",3}<->{"O",1},{"H",4}<->{"C",2}},{{"H",1}<->{"C",1},{"H",2}<->{"C",1},{"H",3}<->{"C",1},{"C",2}<->{"C",1},{"O",1}<->{"C",2},{"C",2}<->{"O",1},{"H",4}<->{"C",2}}}
    show=Graph[#, GraphLayout->"SpringEmbedding",
      VertexStyle->{{"C",_}->Lighter[Black],{"O",_}->Lighter[Red],{"H",_}->LightBlue,{"N",_}-> Lighter[Blue]},
      EdgeStyle-> Darker@Green,VertexSize->{{"C",_}->0.7,{"O",_}->0.5,{"H",_}->0.4,{"N",_}->0.6}, 
      ImageSize->{210,200}]&;
    Multicolumn@DeleteDuplicates[show/@raw]

[![enter image description here][1]][1]

The last one is the same as blue ones (not the red one) in 2D. And `IsomorphicGraphQ` would delete all but first one.

How can I delete these duplicates one? 

Just consider planar isomerism, and I also glad to see if anyone solved 
the stereo isomerism.

  [1]: https://i.sstatic.net/RFmdN.png