The antiferromagnetic structures of Cr-Si solid solutions in the range 1.5-6.0 at.% Si have been studied by neutron powder diffraction. The results confirm that the commensurate antiferromagnetic structure is stabilised at around 1.8 at.% Si. Both the magnetic moment and the Neel temperature are found to decrease with increasing silicon content and tend to zero at about 7.2 at.% Si. There is some evidence that the magnetic electrons are of E_g symme-ry and it is suggested that the reduction of magnetic moment is due to the stabilisation of the I_2g relative to the E_g electrons in the chromium band brought about by the formation of covalent bonds with silicon.