[Pw_forum] hi, I want to ask how to construct R-3c symmetry structure?

[r95222066 at ntu.edu.tw]

Hello,
     I want to ask how to construct R-3c symmetry ? I have used wien2k  
to construct
hexegonal and rhombohedral structure on Ca3Co2O6,and I write the  
position to scf file.
But the scf.out file appeal "no symmetry" message!!
Here is my input data:
----------------------------------------------------------------------
(a) Ca3Co2O6 hexagonal structure scf file
   ibrav = 4, celldm(1) =17.1228,celldm(3)=1.1441342,
     nat= 66, ntyp= 3,nspin=2,
ATOMIC_POSITIONS
Ca  0.369000  0.000000  0.250000
Ca  0.702333  0.666666  0.916666
Ca  0.035666  0.333333  0.583333
Ca  0.000000  0.369000  0.250000
Ca  0.333333  0.035666  0.916666
Ca  0.666666  0.702333  0.583333
Ca -0.369000  -0.369000  0.250000
Ca -0.035666   0.297666  0.916666
Ca  0.297666  -0.035666  0.583333
Ca -0.369000   0.000000  0.750000
Ca -0.035666   0.666666  0.416666
Ca  0.297666   0.333333  0.083333
Ca  0.000000  -0.369000  0.750000
Ca  0.333333   0.297666  0.416666
Ca  0.666666  -0.035666  0.083333
Ca  0.369000   0.369000  0.750000
Ca  0.702333   0.035666  0.416666
Ca  0.035666   0.702333  0.083333
Co  0.000000  0.000000  0.250000
Co  0.333333  0.666666  0.916666
Co  0.666666  0.333333  0.583333
Co  0.000000  0.000000  0.750000
Co  0.333333  0.666666  0.416666
Co  0.666666  0.333333  0.083333
Co  0.000000  0.000000  0.000000
Co  0.333333  0.666666  0.666666
Co  0.666666  0.333333  0.333333
Co  0.000000  0.000000  0.500000
Co  0.333333  0.666666  0.166666
Co  0.666666  0.333333  0.833333
O  0.176400   0.022700  0.114000
O  0.509733   0.689366  0.780666
O  0.843066   0.356033  0.447333
O -0.176400  -0.022700 -0.114000
O  0.156933   0.643966  0.552666
O  0.490266   0.310633  0.219333
O -0.022700  -0.176400  0.614000
O  0.310633   0.490266  0.280666
O  0.643966   0.156933  0.947333
O  0.022700   0.176400  0.386000
O  0.356033   0.843066  0.052666
O  0.689366   0.509733  0.719333
O -0.022700   0.153700  0.114000
O  0.310633   0.820366  0.780666
O  0.643966   0.487033  0.447333
O  0.022700  -0.153700 -0.114000
O  0.356033   0.512966  0.552666
O  0.689366   0.179633  0.219333
O  0.176400   0.153700  0.614000
O  0.509733   0.820366  0.280666
O  0.843066   0.487033  0.947333
O -0.153700  -0.176400  0.114000
O  0.179633   0.490266  0.780666
O  0.512966   0.156933  0.447333
O  0.153700   0.176400 -0.114000
O  0.487033   0.509733  0.552666
O  0.820366   0.843066  0.219333
O -0.153700   0.022700  0.614000
O  0.179633   0.689366  0.280666
O  0.512966   0.356033  0.447333
O  0.153700  -0.022700  0.386000
O  0.487033   0.643966  0.052666
O  0.820366   0.310633  0.719333
-----------------------------------------------------------------------
(b) Ca3Co2O6 rhombohedral structure file
     ibrav = 5, celldm(1) =11.86937,celldm(4)=-0.04466,
     nat= 22, ntyp= 3,nspin=2,
ATOMIC_POSITIONS
Ca  0.619000   0.881000   0.250000
Ca  0.250000   0.619000   0.881000
Ca  0.881000   0.250000   0.619000
Ca  0.381000   0.118999   0.750000
Ca  0.750000   0.381000   0.118999
Ca  0.118999   0.750000   0.381000
Co  0.500000   0.499999   0.500000
Co  0.000000   0.000000   0.000000
Co  0.250000   0.250000   0.250000
Co  0.750000   0.749999   0.750000
O   0.539100   0.209500   0.410000
O   0.410000   0.539100   0.209500
O   0.209500   0.410000   0.539100
O   0.290499   0.960900   0.090000
O   0.960900   0.090000   0.290499
O   0.090000   0.290499   0.960900
O   0.460900   0.790499   0.590000
O   0.590000   0.460900   0.790499
O   0.790499   0.590000   0.460900
O   0.709500   0.039100   0.910000
O   0.039100   0.910000   0.709500
O   0.910000   0.709500   0.039100
---------------------------------------------------------------------
Here is the scf.out file message

      Starting magnetic structure
      atomic species   magnetization
         Ca           0.100
         Co           1.000
         O            0.100

      No symmetry!

    Cartesian axes

      site n.     atom                  positions (a_0 units)
          1           Ca  tau(  1) = (   0.6190000   0.8810000   0.2500000  )
-----------------------------------------------------------------------------

Thanks for your help
                Bing-Hong Chen