# How to draw the 2D representation of ammonia molecule

In the 2D representation of the ammonia molecule, we see one solid line, one solid triangle and one dashed triangle

A plane can be made to pass through any three given points. In other words, we can always find a plane which will pass through any three given points in space. So the central N atom and two H atoms will lie in a plane. Only one H will be out of plane. So I think, in the 2D representation, we need to show two solid lines and one solid triangle. Please give your opinion about this. Thanks

• The image is fine. In the image the H with the straight line is in the plane with the N. The H with the dashed triangle is behind the plane, and the H with the solid triangle is in front of the plane. – MaxW May 21 at 9:30
• You can draw the way you proposed too if you omit the lone pair (l.p.). Currently, the plane is defined by $\ce{\text{l.p.}-N-H}$ and this way the graphical depiction is also consistent with the one of tetrahedral environment of a carbon atom with $\mathrm{sp^3}$ hybridized orbitals. – andselisk May 21 at 10:21

## 1 Answer

According to the rules, yes, Ammonia can be drawn with three of it's atoms in one plane and the other outside the plane. Here's an example, along with a 3D projection:

However, what do you comprehend from this structure? This structure does not convey the trigonal pyramidal geometry of the molecule very convincingly. It might be mistaken for trigonal planar at a glance, and this defeats the purpose of using the wedge/dash notation. Ammonia (and several other tetrahedral molecules) are represented in that manner since it is easiest to interpret their 3d structure from a 2d image.

• The choice is between trigonal pyramidal and trigonal planar. – Karsten Theis May 21 at 10:19