Figure 1

(Color online) A powder diffraction pattern of scandium phase II at $23\mathrm{GPa}$ and its Rietveld refinement. Two insets show enlarged views of the peak top and the background region of the observed diffraction pattern. The $S$ represents the satellite peak which cannot appear in only the host lattice. The I and Re denote diffraction peaks from $\mathrm{Sc}$-I and a gasket material. The upper and lower ticks below the profile mark the positions of the host and guest reflections. The pseudo-Voigt profile function with two refineable parameters of $GW$ and $LY$ without any asymmetry parameters was used for the Rietveld fit. The $R$ factor of the fit was $R_{wp}=3.2\%$. The $R_{wobs}$ for all, the host, and the guest reflections were 8.1%, 7.1%, and 22.4%, respectively.Reuse & Permissions

Figure 2

(Color online) Crystal structure of scandium phase II at $23\mathrm{GPa}$ in projected downward (a) the $c$ axis for $2\times 2$ unit cells and (b) the $b$ axis for $2\times 4$ cells of the host lattice. Here, the ratio $c_1∕c_2$ was assumed to be 3/2.Reuse & Permissions

Figure 3

(Color online) Pressure dependence of the structural parameters of the scandium phase II for (a) the lattice parameters $a_{\mathit{1}}$ $(=a_2)$, $c_{\mathit{1}}$, $c_{\mathit{2}}$, (b) the incommensurability $\gamma$ together with the other members of the $I\mathit{4}∕mcm$ family, and (c) the interatomic distances. The distances $d_{\mathit{1}}$, $d_{\mathit{2}}$, $d_{\mathit{3}}$, and $d_{\mathit{4}}$ are labeled in Figs. 2a and 2b.Reuse & Permissions

Figure 4

(Color online) Pressure dependence of the atomic volume for scandium phase II (squares), together with the previous data for phases I and V (circles) (Ref. 10). Dotted data labeled Ti represent the compression curve of titanium (Ref. 23).Reuse & Permissions