Spatial Orientation of Bonds - Online Tutor, Practice Problems & Exam Prep

Understanding the spatial orientation of bonds is crucial in chemistry, particularly when visualizing molecules in three dimensions. Atoms or groups depicted on solid wedges are oriented above the plane, projecting towards the observer, as if they are coming out of the page. Conversely, atoms on dashed wedges are directed below the plane, pointing away from the observer and into the page. This distinction helps in grasping the 3D arrangement of atoms within a molecule, an essential aspect of molecular geometry which can influence the physical and chemical properties of substances. As you explore skeletal formulas further, recognizing whether a group is on a solid or dashed wedge will elucidate the molecule's spatial configuration.

Spatial Orientation of Bonds

In this video, we're going to take a look at spatial orientation of bonds. Now we're going to say that the skeletal formula also shows how atoms in the molecule are arranged in space in addition to how atoms are bonded. Here we're going to say that atoms or groups on a solid wedge come out of the page, meaning they're above the plane towards the observer. So imagine you're looking at this molecule that OH is pointing straight up at you towards your face. So here this is our solid wedge, meaning that OH is pointing straight out of the paper towards you.

We're going to say next that atoms on dashed wedges go inside the page, they lie below the plane and we're going to say they are away from the observer. So here's our dashed wedged line. That means it goes into the page. So if you want to think about this in terms of 3D, imagine my hand here is a piece of paper. We'd say that the OH is a solid wedge, so it's pointing up towards my face, towards my chin. And then we'd say that this group here, which is a chapter three group, is dash. So it's below. It's on the bottom away from my chin.

So that's what we mean in terms of orientation in space. We can actually say what direction the group is pointing now based on if it's a solid wedge or a dashed wedge. So hopefully that makes more sense. As we delve deeper into skeletal formulas, we'll see these types of bonds pop up here and there.

Spatial Orientation of Bonds Example

Here in this example question it says identify which groups in the given structure are above or below the plane of drawing O. Remember, if you have a solid wedged bond, that means you're above the plane, and if you have a dashed wedge bond you're below the plate.

If we take a look here, at the end of this bond here is a carbon that we don't see. Carbon must make four bonds so it has three hydrogens that are invisible. From this image, we'd say that's what's above plane would be our Chapter Three group, here, this OH group.

And then what's below would be this NH₂ group because it's the one with the dash wedge bond and those are the only bonds that we see that have either a solid wedge or dashed wedge. So those are the only options that we can say, right. So these would be the answer this following example question.

Transform the following skeletal formula so that groups 1 and 2 come out of the page and group 3 goes inside the page.

• A.
• B.
• C.
• D.

Here’s what students ask on this topic:

What is the spatial orientation of the double bond in the molecule below?

To provide an accurate response to your question about the spatial orientation of a double bond in a molecule, I would need to see the specific structure you're referring to. Double bonds in organic molecules, such as those found in alkenes, have a planar geometry due to the nature of the pi bond that constitutes part of the double bond. This pi bond is formed from the sideways overlap of p orbitals from each of the two carbon atoms involved in the double bond.

The double bond restricts rotation, which means that the atoms directly attached to the double-bonded carbons are locked in place relative to each other, leading to the concept of cis-trans (or E-Z) isomerism. In a cis configuration, the higher priority groups (based on Cahn-Ingold-Prelog priority rules) on each carbon are on the same side of the double bond, while in a trans configuration, they are on opposite sides.

For a specific molecule, the spatial orientation would depend on the arrangement of these groups and the specific stereochemistry of the double bond. If you can provide the structural formula or name of the molecule, I could give a more detailed explanation of its double bond orientation.