用蒸气压渗透法和红外光谱法测定了2-乙基己基膦酸单2-乙基己基酯[HEH(EHP),以下简称 HA]与钕的萃合物在含有不同浓度的 HA-正己烷溶液中的平均聚合度.NdA_3在37℃下的正己烷中溶解度约为1.2×10~(-2)mol·dm~(-3),此时 NdA_3的平均聚合度为7,(?)取桥式与钕配位.向该溶液中不断加入 HA 时,生成 NdA_3·nHA(n=1,2,3),部分桥式配位被单齿配位的(?)所取代,同时平均聚合度下降,当~C(HA)/~CNdA_3≥3时,平均聚合度下降为1,桥式配位的膦氧桥大部分被单齿配位的膦氧根所代替.在所有情况下钕的配位数均为6. The extraction of 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester [HEH (EHP), hereinafter referred to as HA] and neodymium in the presence of different concentrations of HA-n-hexane Solution.The average degree of polymerization of Nd 3 is about 1.2 × 10 -2 mol · dm -3 in n-hexane at 37 ℃, and the average degree of polymerization of NdA 3 is 7 Bridging and neodymium coordination. When HA was added to the solution, NdA_3 · nHA (n = 1, 2, 3) was generated and part of the bridged coordination was replaced by ()) with monodentate coordination, meanwhile the average degree of polymerization , The average degree of polymerization decreases to 1 when ~ C (HA) / ~ CNdA_3≥3, and most of the bridged phosphine oxygen bridges are replaced by phosphine oxides with monodentate coordination. In all cases, The median is 6.