# Nsites for magnetic structures

For AFM NiO, https://materialsproject.org/materials/mp-19009/
the material explorer shows Nsites=2 as it does for other rocksalt structures, however it shows the volume of the magnetic supercell (twice the primitive rocksalt cell). Am I missing something, is it a bug or a feature? How can I screen by volume-per-atom for all materials, including those with non-trivial magnetic order?

Just realized this was reported already:

In the latter case, the positions themselves are not equivalent, presumably too large a tolerance was used in the symmetrization routine (and different tolerance for volume and Nsites determination).

However, the former case, just as the one in the OP (mp-19009), is AFM, so a correction to Nsites is non-trivial and due to the true (magnetic) unit cell being twice the unit cell of the atomic structure… Sorry if I’m saying something obvious, just wanted to draw your attention to this potential complication in fixing the problem.