Synthesis, crystal and electronic structures of La3Cr2N6

The rare earth–transition metal ternary nitride La3Cr2N6 was synthesized from the elements and an excess of sodium and gallium at 900 ∘C in a sealed niobium tube. This compound crystallizes in the tetragonal space group I 4 / m m m (No. 139) with a = 3.8525 ( 5 ) Å and c = 20.508 ( 4 ) Å . It is isostructural with the recently discovered ternary nitrides R3M2N6 (R=La, Ce or Pr; M=V, Nb or Ta) and with the high T c superconducting copper oxide La2−xSrxCaCu2O6. Band structure calculations using density functional theory show that La3Cr2N6 contains CrN2 conducting layers.