Why are the lone pairs in the diagram below connected with dashed lines and triangular shapes? Do they signify anything?

enter image source here

I understand that the three electron pairs will repel each other to form a linear bond but then why does the diagram include triangles as an indication for a bond? (They are in blue)

If anyone could help, I'd appreciate it. Thx:-)

1 Answer

Here's what's going on here.


The #"AX"_2"E"_3# molecule shown in that image was drawn using wedge-dash notation, which is a way of drawing #"3D"# molecules on a #"2D"# plane such as a paper.

The idea here is that you have

  • regular lines #-># they are located in the plane of the page

  • dashes #-># they are directed behind the page

  • wedges #-># they are coming out of the page


In your case, you have two single bonds to #"X"# and one lone pair drawn using regular lines, which means that they are in the plane of the page.

The lone pair placed on the dash is being drawn going away from you, behind the plane of the page.

The lone pair placed on the wedge is being drawn coming at you, in front of the plane of the page.