Structure of Boron carbide (B4C) ceramic

Dear all,

I need to simulate the composites reinforced with WC, SiC and B4C nanoparticles. the the WC and SiC unit cells are  available in "Structures" directory, but I couldn't find that of B4C (Boron carbide). where can I find it, or how can I build it?

Thanks

Farzin