The Synthesis and Characterization of Four New Uranium(IV) Chlorophosphates: UCl4(POCl3), [U2Cl9][PCl4], UCl3(PO2Cl2), and U2Cl8(POCl3)

The new uranium­(IV) chlorophosphate compounds UCl4(POCl3) and [U2Cl9]­[PCl4] have been synthesized by the solid-state reactions of U, P2O5, and PCl5 at 648 K; the compounds UCl3­(PO2Cl2) and U2Cl8­(POCl3) have been synthesized at 648 K with the same reactants plus added S. Their structures are, respectively, chainlike, a simple salt, three-dimensional, and sheetlike. From ab initio calculations, U2Cl8­(POCl3) and UCl3­(PO2Cl2) are found to be ferromagnetic, whereas UCl4­(POCl3) is found to be antiferromagnetic. U2Cl8­(POCl3) is a strong metal, whereas UCl3­(PO2Cl2) is a weaker metal. In contrast, UCl4­(POCl3) has a finite band gap, with a value of 0.35 eV.

通过金属铀、五氧化二磷（P₂O₅）与五氯化磷（PCl₅）在648 K下的固相反应，成功合成了新型铀(IV)氯磷酸盐化合物UCl₄(POCl₃)与[U₂Cl₉][PCl₄]；以相同反应物外加单质硫为加料，在同等温度条件下可制得UCl₃(PO₂Cl₂)与U₂Cl₈(POCl₃)。上述四种化合物的晶体结构依次为链状、简单盐型、三维骨架型与层状。通过从头算（ab initio calculations）计算发现，U₂Cl₈(POCl₃)与UCl₃(PO₂Cl₂)具有铁磁性，而UCl₄(POCl₃)呈现反铁磁性。其中U₂Cl₈(POCl₃)属于强金属性材料，UCl₃(PO₂Cl₂)的金属性较弱；与之相对，UCl₄(POCl₃)存在有限带隙，带隙值为0.35 eV。