Fig. 3. The pressure dependence of the volume per Y atom in the range of 1 bar to 170 GPa for the Y allotropes and the hydrides as determined from the experimental data.
The data for the hexagonal hP3-Y-II and tetragonal tI8-Y allotropes, for tI2-YH3±δ, cF4-YH3, hP3-Y3H11, hP2-Y2H9, cP8-Y4H23, cF80-Y4H25, and hP26-Y13H75, which were obtained in this work, are shown in red, blue, green, brown, orange, cyan, and violet circles, respectively. The experimental pressure dependence of the volume per Y atom for yttrium allotropes published in (34) is shown in small black circles; the experimental values for cF4-YH3 and hP3-Y3H11 from (32) are shown as open blue and green symbols, respectively. Pearson symbols refer to the arrangement and content of Y atoms only.