Separation of rare earth element radioisotopes by reverse-phase high-speed counter-current chromatography.

Analytical scale purification of rare earth element (REE) radioisotopes is typically accomplished using cation-exchange resins (e.g. AG 50W-X8) and high-performance liquid chromatography (HPLC).

Cs[TfN]: a second polymorph with a layered structure.

The structural determination of the ionic liquid, caesium bis-[(tri-fluoro-meth-yl)sulfon-yl]imide or poly[[μ-bis-[(tri-fluoro-meth-yl)sulfon-yl]imido]caesium(I)], Cs[N(SOCF)] or Cs[TfN], reveals a second polymorph that also crystallizes in a layer structure possessing monoclinic 2/ symmetry at 120 K instead of 2/ for the known polymorph [Xue (2002 ▸). , 1535-1545]. The caesium ions in the cationic layers are coordinated by the sulfonyl groups of the bis-triflimide mol-ecules from anion layers while the tri-fluoro-methyl groups are oriented in the opposite direction, forming a non-polar surface separating the layers.