Is the Hybridization of AsH3 sp3 or sp3d?

[h20h]

HI! I have a quick question...we were asked on a quiz to draw the lewis dot structure for AsH3. Then describe the bonding scheme for the molecule in terms of hybridization.

I wrote that since As is in group 5...it has 5 electrons with 3 H bonded to it. In lab we were told to count lone pairs as one, so wouldn't you need 2 lone pairs to get up to 5 electrons? Or do you count the individual electrons individually? That is where I am confused...becuase if you count the lone pair as one group you would need another lone pair to get to 5? She gave us an answer for the hybridization of sp3 where I said sp3d...can you explain please?

Thanks
h20h

 

[dextercioby]

The As has 5 binding electrons, and uses 3 to form covalent bounds with H. The other 2 form a lone pair. The situation is identical with ammonia NH_{3}. The hybridization for ammonia is sp_{3}. The same goes for water H_{2}O, but for the latter, there are 2 lone pairs from the 6 valence electrons of O.

 

[Blueshift5]

2o

Hi h20h2o,

Thank you for your question. The hybridization of AsH3 is sp3. This means that the central atom, As, has four electron domains (three bonding pairs and one lone pair) and therefore requires four hybrid orbitals for bonding. The four hybrid orbitals are formed by mixing one s orbital and three p orbitals, resulting in four sp3 hybrid orbitals.

In terms of the Lewis dot structure, AsH3 has three single bonds between As and H, and one lone pair on As. The lone pair is not considered as a separate group, but rather as one of the four electron domains that require hybridization.

It is important to note that the hybridization of a molecule is determined by the number of electron domains around the central atom, not the number of atoms bonded to it. In this case, As has four electron domains, so it requires sp3 hybridization.

I hope this helps clarify the confusion. Let me know if you have any further questions. Good luck with your studies!