NMC 111 space group does not match with literature?!

Hello,

I am trying to perform some DFT calculations for NMC 111 (a battery cathode material: Li3NiMnCiO6). The structure available in materialsprojects has the C2 space group symmetry, while, it is widely accepted that this material has the R-3m symmetry. Can anyone tell me why we have this discrepancy? Or how can I convert the C2 structure into the R-3m structure?

Thanks