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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: ThePhenom on February 20, 2008, 06:25:08 PM

Title: Expanded Valence
Post by: ThePhenom on February 20, 2008, 06:25:08 PM

Im not sure why sulfur is able to bond with six different atoms at once, and why phosphorus can also achieve an expanded valence.  ???

Title: Re: Expanded Valence
Post by: wilson300 on February 21, 2008, 01:04:35 AM

S and P have orbitals 3s, 3p and 3d. If 3s and 3p are filled up, an expanded valence can be achieved by filling up the 3d orbital.

Title: Re: Expanded Valence
Post by: AWK on February 21, 2008, 01:07:10 AM

see at electronic structure of:
PCl₅, HPF₆

Title: Re: Expanded Valence
Post by: ThePhenom on February 21, 2008, 08:42:39 PM

Quote from: wilson300 on February 21, 2008, 01:04:35 AM

S and P have orbitals 3s, 3p and 3d. If 3s and 3p are filled up, an expanded valence can be achieved by filling up the 3d orbital.

Why does this happen though?

Title: Re: Expanded Valence
Post by: agrobert on February 21, 2008, 09:03:56 PM

It is actually a topic that is not fully understood.  Depending on your class it may be acceptable to say that sulfur accesses higher valence shells but some would say that it is much more complicated than this.

http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/1986/108/i13/f-pdf/f_ja00273a006.pdf?sessid=6006l3

Title: Re: Expanded Valence
Post by: DonalB on February 28, 2008, 06:39:45 AM

Have you studied hybridized orbitals in your class?