(CHEMISTRY) Wedge/Dash Structures help!

Question

I'm not sure of the wedge and dash structures for fromaldehyde, sulfite ion, and boron trichloride. I can't seem to find any information about it :(

Thank you for your help!

Answer 1

Hi Adwad--

Boron trichloride and formaldehyde both have trigonal planar geometry. Due to this, they don't require wedges and dashes when drawing them (they exist in the plane of the screen/paper/board/etc).

Sulfite has 4 groups coming off of the sulfur, giving it a tetrahedral electronic geometry. Because one of the groups is a pair of non-bonding electrons, the molecular geometry is "trigonal pyramidal." I included the structures below, with the 3-dimensional structure of the sulfite ion represented with a wedge and dash.

When learning electronic and molecular geometry, the link below includes a useful table. Good luck!

https://ontrack-media.net/gateway/chemistry/g_cm3l4rs5.html