Table 1 The unit-cell parameters and atomic positions of the I4/mcm, P-1, P6/mmm and C2/m phase at 0 GPa, 40 GPa, 100 GPa and 300 GPa, respectively.
Space group | Pressure (GPa) | Lattice parameters (Å, ˚) | Atom | Wyckoff positions | x | y | z | |
|---|---|---|---|---|---|---|---|---|
I4/mcm | 0 | a = 6.2871 (6.3098) | α = 90 | Rb | 4a | 0 | 0 | 0.25 |
b = 6.2871 (6.3098) | β = 90 | N1 | 8h | 0.3664 | 0.1336 | 0 | ||
c = 7.5106 (7.5188) | γ = 90 | N2 | 4d | 0.5 | 0 | 0 | ||
P-1 | 40 | a = 3.3263 | α = 96.7544 | Rb | 2i | 0.8007 | 0.9350 | 0.7555 |
b = 4.7467 | β = 75.1448 | N1 | 2i | 0.1171 | 0.5467 | 0.8935 | ||
c = 5.5230 | γ = 97.8611 | N2 | 2i | 0.4330 | 0.6051 | 0.4513 | ||
N3 | 2i | 0.6319 | 0.6399 | 0.2184 | ||||
P6/mmm | 100 | a = 5.5482 | α = 90 | Rb | 2d | 0.3333 | 0.6667 | 0.5 |
b = 5.5482 | β = 90 | N | 6j | 0.7684 | 0.7684 | 0 | ||
c = 5.5482 | γ = 120 | |||||||
C2/m | 300 | a = 3.9946 | α = 90 | Rb | 4i | 0.2234 | 0 | 0.3843 |
b = 4.0911 | β = 98.6538 | N1 | 8j | 0.8612 | 0.2517 | 0.9327 | ||
c = 6.1675 | γ = 90 | N2 | 4i | 0.8201 | 0.5 | 0.8029 | ||
