Desktop Sandy Bridge uses socket 1155
 

Intel might be playing its little game again. Last year before it officially introduced Core i7 and Core i3 based Clarkdale CPUs, it claimed that the new CPU has socket 1155. Later in 2009 it said to its partners that the new socket ends up with 1156 pins. The name of the Sandy Bridge desktop socket, for now, is LGA1155 and we are not sure if its pin compatible with Intel's last socket LGA 1156 Core 2010 based CPUs. Even if it is, Sandy Bridge dual and quad cores should not work in current LGA 1156 pin 5 series chipset based motherboards simple as Sandy Bridge needs a 6-series chipset.

http://www.fudzilla.com/content/view/17871/35/