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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: pele on January 29, 2007, 02:30:50 PM

Title: bond angles
Post by: pele on January 29, 2007, 02:30:50 PM

Please help me with bond angles in molecule of SOCl2 !!! What angles approximately are there in molecule and how can I know that?

P.S sorry about my English

Title: Re: bond angles
Post by: Yggdrasil on January 29, 2007, 02:34:02 PM

The first step is to draw a lewis structure of SOCl₂

Title: Re: bond angles
Post by: pele on January 29, 2007, 02:49:01 PM

Ok.I think I managed to draw it, but  I still don't have no idea about angles.

Title: Re: bond angles
Post by: english on January 29, 2007, 03:37:14 PM

What molecular geometry can you infer from the VSEPR model?

Title: Re: bond angles
Post by: pele on January 29, 2007, 04:00:13 PM

I don't know. I tried to use isis/draw and search google, but no results ??? >:(

Title: Re: bond angles
Post by: english on January 29, 2007, 04:12:35 PM

Quote from: pele on January 29, 2007, 04:00:13 PM

I don't know. I tried to use isis/draw and search google, but no results ??? >:(

http://en.wikipedia.org/wiki/VSEPR.

Title: Re: bond angles
Post by: Yggdrasil on January 29, 2007, 06:56:34 PM

What does your lewis structure look like?  What is the central atom?  How many atoms are bonded to the central atom?  How many lone pairs are on the central atom?

Title: Re: bond angles
Post by: pele on January 30, 2007, 08:06:38 AM

the central atom is "S" 3 atoms are bonded to it. (one is double bond with "O")

Title: Re: bond angles
Post by: GreenHorn on January 30, 2007, 08:54:08 AM

Well if there are 4 pairs of electrons (2 pairs on the double bond and 2 to the two chlorides)  the coordination number is 4, and thus the bond angle is 109 degrees? Correct me if im wrong...

Title: Re: bond angles
Post by: Yggdrasil on January 30, 2007, 02:03:55 PM

Quote from: pele on January 30, 2007, 08:06:38 AM

the central atom is "S" 3 atoms are bonded to it. (one is double bond with "O")

Are there any lone pairs?

Title: Re: bond angles
Post by: pele on January 31, 2007, 01:53:00 PM

If I understood correctly, than "S" has  2 alone electrons in the 3p orbital.

Title: Re: bond angles
Post by: Yggdrasil on February 01, 2007, 03:11:35 AM

In SOCl₂ there is a lone pair (although it is not in a 3p orbital, remember that atomic orbitals become hybridized when atoms are bonded to each other).  So, there are three atoms bonded to the sulfur and a lone pair.  This defines four "electron domains" (called steric number on the wikipedia site) which means that there will be a tetrahedral geometry about the sulfur.  Since three of the four electron domains are bonds, this leads to a trigonal pyramidal shape.

For more descriptions of how geometries of molecules relates to the number of "electron domains" and number of bonds v. lone pairs, see the chart at http://en.wikipedia.org/wiki/VSEPR