  The electronic and magnetic structures of A2CrN3 (A = Ce, U) ternary
compounds calculated based on band magnetism within DFT exhibit different
behaviors of the nf elements (n = 4, 5 resp.). Charge analysis allows to
formally express the two compounds as A2Cr 5+ N3 5- thus classifying them as
covalent nitrides, i.e. far from formal exchange of +- 9 electrons. From
establishing the energy-volume equations of state, the two compounds are found
with hardness magnitudes: B0(A=Ce) =192 GPa and B0(A=U) = 243 GPa, within range
of oxides due to covalent metal-nitrogen bonding shown as based on overlap
matrix analysis. The uranium compound is harder due to a smaller volume and
less compressible U versus Ce metals. Ce2CrN3 exhibits large magnetization on
Cr (1.94BM) and a very small moment develops on cerium (0.14 BM) pointing out
to an intermediate valence state while in U2CrN3, M(Cr) = 0.49 BM and M(U) =
0.97BM. These results are stressed by broad band-like density of states (DOS)
behavior for A=U and localized DOS for A=Ce. Both compounds are found
ferromagnetic in the ground state
