$\ce{SF6}$ does not expand it octet by way of using 3d orbitals.  It is often taught that way, particularly in introductory classes.  A better description involves treating it as a hypercoordinated molecule.  See these earlier answers for an explanation of how hypercoordination can be applied.  When finished you should be able to apply the concept to $\ce{SF6}$.


reference 1
reference 2


$\ce{BF3}$ is electron deficient and reacts rapidly with molecules containing lone pairs of electrons (amines, oxygen containing compounds, etc.) to stabilize the octet configuration.  It has also been observed that the $\ce{B-F}$ bond length is somewhat shorter than expected.  This has been explained by invoking resonance structures such as



and



To whatever degree these types of resonance structures contribute to the true description of $\ce{BF3}$ they help explain the shortened bond length and also achieve an octet around the central boron.

A similar explanation can be applied to $\ce{SnCl2}$, drawing a resonance structure with a $\ce{Sn=Cl}$ double bond creates an octet around the central tin atom.  To whatever degree such resonance structures contribute to the real description of $\ce{SnCl2}$, they will help satisfy the octet electronic configuration around the central tin atom.

Why does SnCl2 occur despite the octet rule?
I have several hosted wordpress blogs, and I've been trying to visit them and they are really slow. I looked at my server logs and I found this

stanfordflipside.com:80 188.138.33.149 - - [17/Aug/2013:17:14:28 -0700] "POST /xmlrpc.php HTTP/1.1" 200 595 "-" "GoogleBot/1.0"
stanfordflipside.com:80 188.138.33.149 - - [17/Aug/2013:17:14:28 -0700] "POST /xmlrpc.php HTTP/1.1" 200 595 "-" "GoogleBot/1.0"
stanfordflipside.com:80 188.138.33.149 - - [17/Aug/2013:17:14:28 -0700] "POST /xmlrpc.php HTTP/1.1" 200 595 "-" "GoogleBot/1.0"
stanfordflipside.com:80 188.138.33.149 - - [17/Aug/2013:17:14:28 -0700] "POST /xmlrpc.php HTTP/1.1" 200 595 "-" "GoogleBot/1.0"
stanfordflipside.com:80 188.138.33.149 - - [17/Aug/2013:17:14:29 -0700] "POST /xmlrpc.php HTTP/1.1" 200 595 "-" "GoogleBot/1.0"
stanfordflipside.com:80 188.138.33.149 - - [17/Aug/2013:17:14:29 -0700] "POST /xmlrpc.php HTTP/1.1" 200 595 "-" "GoogleBot/1.0"
stanfordflipside.com:80 188.138.33.149 - - [17/Aug/2013:17:14:29 -0700] "POST /xmlrpc.php HTTP/1.1" 200 595 "-" "GoogleBot/1.0"
stanfordflipside.com:80 188.138.33.149 - - [17/Aug/2013:17:14:29 -0700] "POST /xmlrpc.php HTTP/1.1" 200 595 "-" "GoogleBot/1.0"
stanfordflipside.com:80 188.138.33.149 - - [17/Aug/2013:17:14:31 -0700] "POST /xmlrpc.php HTTP/1.1" 200 595 "-" "GoogleBot/1.0"
stanfordflipside.com:80 188.138.33.149 - - [17/Aug/2013:17:14:31 -0700] "POST /xmlrpc.php HTTP/1.1" 200 595 "-" "GoogleBot/1.0"
stanfordflipside.com:80 188.138.33.149 - - [17/Aug/2013:17:14:31 -0700] "POST /xmlrpc.php HTTP/1.1" 200 595 "-" "GoogleBot/1.0"


I am getting ~10 hits per second to the file /xmlrpc.php from the GoogleBot to several sites, and this seems to be slowing down the server. I am running 

tail -f 


on the log file, and can just see these requests continuing. Does anyone know why this might be happening or what you could do to stop it?
