# Molecular Structure

What's the meaning of the triangle and striped line in this structure of $$\ce{H3O+}$$:

(I'm quite a novice in chemistry.)

Thanks

It is the way how to display the 3D structure of molecules on the 2D plane.

Imagine that

• Atomic bonds represented by a normal line are placed on the plane of a paper/screen.
• Atomic bonds represented by triangles point toward you from the plane.
• Atomic bonds represented by stripes point behind the plane.

It is frequently used in organic chemistry, where the particular 3D structure matters, especially for optically active molecules (Their mirror image is not the identical molecule).

See the andselisk comment above.

• But how will I show the double and triple bonds then? – Shub Aug 13 '20 at 13:37
• Arrange them to be in the plane :-) E.g. both ethene and ethyne are planar. – Poutnik Aug 13 '20 at 13:39