Question

how to find the structures for molecules??

Answer 1

There are many techniques which a chemist can use to identify the structures for a molecule, such as using IR spectroscopy, H-NMR, C-NMR, X-ray diffraction, mass spectroscopy, or Raman spectroscopy. I am sure there is a few other methods but these are the main ones.

Answer 2

For small molecules, like \(CH_4 \;or\;PCl_3 \), you can approximate their shape with VSPER.