Synthesis and Structure of Two New Layered Ternary Nitrides, SrZrN₂ and SrHfN₂

Abstract

The new ternary nitrides SrZrN2 and SrHfN2 have been synthesized by the solid state reactions of Sr2N with ZrN and HfN and characterized by powder X-ray diffraction. Both nitrides form structures in the hexagonal space group R3̄m (SrZrN2, a = 3.37302(5) Å, c = 17.6756(3) Å, Z = 3; SrHfN2, a = 3.34481(3) Å, c = 17.6779(2) Å, Z = 3) and are isostructural with α-NaFeO2. The structures are constructed of alternating layers of strontium−nitrogen edge-sharing octahedra and either zirconium−nitrogen or hafnium−nitrogen edge-sharing octahedra stacked along the c axis. Alternatively, Sr2+ can be regarded as occupying octahedral holes between Zr(Hf)N2 octahedral layers. The title nitrides are essentially diamagnetic at room temperature, consistent with the chemical composition. These compounds are the first alkaline earth ternary nitrides observed to have the α-NaFeO2 layered structure.

Synthesis, Structure, and Magnetic Properties of the New Ternary Nitride BaHfN2and of the BaHf1−xZrxN2Solid Solution

“…Known examples of ternary nitridohafnates are not numerous and only one ternary alkaline earth hafnium nitride, SrHfN , has been previously reported (21). The hafnium coordination in this compound is octahedral, with six distances to nitrogen of 2.273(2) A s .…”

“…The latter tantalum material has attracted particular interest on account of the superconducting transition reported in this nitride at ca. 9.6 K. Magnetic measurements conducted on SrZrN and SrHfN suggest these materials are intrinsically diamagnetic at room temperature (21). BaZrN , however, shows anomalous magnetic behavior for a material of presumed s"0 electronic configuration, exhibiting temperature-independent paramagnetism between 20 and 300 K (20).…”

“…BaZrN is isotypic with KCoO , which contains layers made up of edge-sharing Zr-N square-base pyramids (20). The nitrides SrZrN , SrHfN (21), and CaTaN (22) all form structures isotypic with -NaFeO . The latter tantalum material has attracted particular interest on account of the superconducting transition reported in this nitride at ca.…”

Structural, mechanical, electronic and optical properties of layered ternary nitrides SrZrN 2 and SrHfN 2 : First-principles calculations

“…Many efforts have been made to study transition-metal nitrides in the last decades [2][3][4][5][6][7][8][9]. Especially the ternary transition-metal nitrides featuring two metals have attracted wide attention and developed dramatically such as MWN 2 with M = Mn, Co, Ni, Fe [10,11], BaMN 2 with M = Zr, Hf [2,5,6,12], SrMN 2 with M = Ti, Zr, Hf [2,3,6,13,14], and [2,15,16].…”

“…This is due to the fact that the formal d-electron count d 0 for the M atom [3,13,14] introduces new properties and expands their application range of ternary nitrides of stoichiometry AMN 2 (A = alkali, alkaline earth or transition metal; M = lanthanide or transition metal). However, alkaline earth ternary nitrides are rarely studied.…”