8
The staggered conformation of ethane has D3d symmetry
1   0.000000000  -1.024342948   1.140400499
6   0.000000000   0.000000000   0.756028963
1  -0.887107016   0.512171474   1.140400499
6  -0.000000000   0.000000000  -0.756028963
1   0.887107016   0.512171474   1.140400499
1  -0.887107016  -0.512171474  -1.140400499
1   0.887107016  -0.512171474  -1.140400499
1  -0.000000000   1.024342948  -1.140400499
