Hybridization and Geometry of OH- Ion

Click For Summary

Discussion Overview

The discussion centers around the hybridization and molecular geometry of the hydroxide ion (OH-), exploring the Lewis structure, bonding domains, and the implications of hybridization on molecular shape. Participants examine the relationship between electron configuration and molecular geometry, considering both theoretical and practical aspects of the topic.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant describes the Lewis structure of OH-, noting 6 electrons around the oxygen atom and suggesting tetrahedral geometry based on 3 lone pairs and 1 bonding domain, while expressing uncertainty about the shape possibly being linear.
  • Another participant emphasizes that when discussing molecular shape, the focus should be on the positions of atoms rather than orbitals, suggesting that NH3 is not tetrahedral in terms of molecular geometry.
  • Some participants assert that there are no empty 2s orbitals in oxygen, prompting a clarification that the reference was intended for 2p orbitals instead.
  • One participant argues that hybridization is necessary for understanding the bond angles in H2O and OH-, suggesting that the bond angle in H2O being closer to 109 degrees indicates the involvement of hybridization.
  • There is a discussion about whether the same reasoning applied to H2O could be used to argue against hybridization in OH-, with some participants questioning the implications of such reasoning.

Areas of Agreement / Disagreement

Participants express differing views on the necessity and implications of hybridization in the context of OH- and H2O, indicating that there is no consensus on the role of hybridization in determining molecular geometry.

Contextual Notes

Participants highlight the importance of distinguishing between electron configuration and molecular geometry, noting that the effective bonds must be considered in the analysis. There are unresolved questions regarding the role of hybridization in determining bond angles and molecular shape.

lkh1986
Messages
96
Reaction score
0
Question: State the hybridization used and the molecular geometry shape of hydroxide ion, OH-.

Okay, so I draw out the Lewis structure, where there are 6 electrons (3 lone pairs) around the O atom, which is bonded to the H atom. So, I think base on the 3 nonbonding domains and 1 bonding domain, I think the shape is tetrahedral, but it seems weird to me, because I think it may be linear.

Then, regarding the hybridization, I think the O atom uses sp3 hybridization, but then again, I think there is no hybridization involved, because O can use the remaining empty 2s orbital to bond to the only one electron from H atom.

Which one is the correct one? :confused:
 
Physics news on Phys.org
lkh1986 said:
Question: State the hybridization used and the molecular geometry shape of hydroxide ion, OH-.

Okay, so I draw out the Lewis structure, where there are 6 electrons (3 lone pairs) around the O atom, which is bonded to the H atom. So, I think base on the 3 nonbonding domains and 1 bonding domain, I think the shape is tetrahedral, but it seems weird to me, because I think it may be linear.
When you are asked for the shape of the molecule/ion, you are asked to describe the relative positions of the atoms, not the relative positions of the orbitals. If you were going to describe the geometry of the orbitals (instead of the geometry of the atoms) then you'd say NH3 was tetrahedral (instead of a trigonal pyramid).

Then, regarding the hybridization, I think the O atom uses sp3 hybridization, but then again, I think there is no hybridization involved, because O can use the remaining empty 2s orbital to bond to the only one electron from H atom.
What empty 2s orbital? Is there an empty 2s in oxygen?
 
First: Identify the number of valence electrons present in the total compound.
Second: Draw the Lewis structure
Third: Remember that though the electron configuration maybe tetrahedral that does not mean that the whole molecule will have that shape. You must look at the total 'effective bonds'.

I agree with Gokul, there are no empty 2s orbitals for O. Look at everything again. Hope that helps.
 
Gokul43201 said:
What empty 2s orbital? Is there an empty 2s in oxygen?

Oh, sorry, typo there. I mean 2p orbital.
 
Okay, that makes more sense. But now, it seems you need to understand how hybridization works.

You could as well ask a similar question regarding the H2O structure. After all, you could just as well argue that the 2 vacancies in the 2p orbitals can be used to accommodate the electrons from the 2 H atoms. So, the exact same argument as the one above, would lead you to conclude that H2O requires no hybridization either.

If that were true, why then, is the H-O-H bond angle much closer to 109 than it is to 90 deg? Clearly, hybridization is involved in H2O, as it will be in the case of OH-. The reason that hybrid orbitals are closer to reality is due to the reduction in energy that results from hybridization.
 

Similar threads

Chemistry How to understand hybridization in ##CH_3NNN##?
  • · Replies 4 ·
Replies
4
Views
3K
Energy level Diagram relating to SP3 hybridization
  • · Replies 2 ·
Replies
2
Views
7K
Organic chemistry hybridization and bond angles
  • · Replies 1 ·
Replies
1
Views
4K
Predict the hybridization and geometry of the indicated atom
  • · Replies 2 ·
Replies
2
Views
3K
Chemistry How do we know ##BF_3## has Lewis structure but ##Al_2S_3## does not?
  • · Replies 1 ·
Replies
1
Views
2K
Chemistry Predicting the electron domain and molecular geometries
  • · Replies 2 ·
Replies
2
Views
3K
Is there hybridization in the (C2)2+ ion?
  • · Replies 1 ·
Replies
1
Views
13K
Chemistry All possible resonance structures for SO4 2-
  • · Replies 9 ·
Replies
9
Views
13K
Is Dragos rule evidence of hybridization theory's failure?
  • · Replies 9 ·
Replies
9
Views
3K
Ochem - linear combination of atomic orbitals
  • · Replies 1 ·
Replies
1
Views
2K