Stable nitrogen-rich yttrium nitrides under high pressure

Novel high-pressure phases of nitrogen-rich Y–N compounds

“…S3(b) and (c)†). Among the predicted structures above, except for Fm 3̄ m -YN, P 4/ nmm -YN, P 1̄-YN 3 , C 2/ m -YN 4 , and P 1̄-YN 4 , 72–74 there are five novel thermodynamic stable structures ( I 4̄3 d -Y 4 N 3 , R 3 c -Y 2 N 3 , P 1̄-II-YN 4 , P 1̄-YN 6 , and P 31 c -YN 8 ) predicted in this work. Furthermore, the dynamical stability and mechanical stability of the five thermodynamic stable structures at their predicted pressures are confirmed by the calculations of phonon dispersion and elastic constants 75 (Fig.…”

“…6 and P31c-YN 8 are determined as(27, 150 GPa) and (132, 150 GPa), respectively (Fig.S3(b) and (c) †). Among the predicted structures above, except for Fm3 ˉm-YN, P4/nmm-YN, P1 ˉ-YN 3 , C2/m-YN 4 , and P1 ˉ-YN 4 ,[72][73][74] there are five novel thermodynamic stable structures (I4 ˉ3d-Y 4 N 3 , R3c-Y 2 N 3 , P1 ˉ-II-YN 4 , P1 ˉ-YN 6 , and P31c-YN 8 ) predicted in this work.…”

Single-bonded nitrogen chain and porous nitrogen layer via Ce–N compounds

“…It is worth noting that such kind of poly-nitrogen network has been first predicted in K 2 N 16 by Steele and Oleynick in 2017, 60 and then in high-pressure XeN 8 and Xe(N 8 ) 2 (N 2 ) solid-state compounds, 61 and then in YN 8 in 2022. 62 For the P 2 1 CeN 8 , the average distance between two adjacent layers is about 2.38 Å at 60 GPa. The top layer has a shift of about half the lattice along the [101] direction as compared to the bottom layer.…”

Systematical High-Pressure Study of Praseodymium Nitrides in N-Rich Region

“…Theoretically, numerous candidates of polynitrides have been predicted, such as the ring-shaped alkaline metal nitrides with the stoichiometry of MN3 or MN5 (M = Li, Na, K, Rb, Cs), [27][28][29][30][31] the 1-D chain-like alkaline earth metal nitrides MN4 (M = Be, Mg, Ca, Sr and Ba), [32][33][34][35][36][37] the 2-D layered structures formed in transition metal nitrides K2N16, CoN8, CoN10, and YN8, etc., the 3-D extended network structures in ZnN6, 0-D cage-like N10 structure in LaN10 and the molecular sieve porous structure in CeN14. [38][39][40][41][42][43][44] Experimentally, the N4 molecular chain in TaN4, the infinite N-chain in tr-BeN4/FeN4/ZnN4/TaN5, the N5 ring in LiN5/CsN5, N18 rings in YN6, the infinite helical chain in Hf2N11 are synthesized at 100, 85/105/63/100, 45/65, 100, and 105 GPa, respectively. [45][46][47][48][49][50][51][52][53] The decompress studies show that the TaN4, tr-BeN4, FeN4, ZnN4, LiN5, TaN5, CsN5 are quenched to 35,34,23,11,35, 0, and 18 GPa, respectively.…”