Mizoguchi Hiroshi, Gray Danielle, Huang Fu Qiang, Ibers James A
Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.
Inorg Chem. 2006 Apr 17;45(8):3307-11. doi: 10.1021/ic052140l.
The compounds K0.91U1.79S6 and KU2Se6, members of the AAn2Q6 actinide family (A = alkali metal or Tl; An = Th or U; Q = S, Se, or Te), have been synthesized from US2, K2S, and S at 1273 K and U, K2Se, and Se at 1173 K, respectively. KU2Se6 shows Curie-Weiss behavior above 30 K and no magnetic ordering down to 5 K. The value of mu(eff) is 2.95(1) mu(B)/U. Its electronic spectrum shows the peaks characteristic of 5f-5f transitions. It is a semiconductor with an activation energy of 0.27 eV for electrical conduction. Both K0.91U1.79S6 and KU2Se6 crystallize in space group Immm of the orthorhombic system and are of the KTh2Se6 structure type. Both contain infinite one-dimensional linear Q-Q chains characteristic of the AAn2Q6 family. Typical of the known AAn2Q6 compounds, in KU2Se6, there are two alternating Se-Se distances of 2.703(2) and 2.855(2) A, both much longer than an Se-Se single bond. In contrast, in K0.91U1.79S6, the first sulfide of this family to be characterized structurally, there are alternating normal S2(2-) pairs 2.097(5) A in length. In K0.91U1.79S6, the formal oxidation state of U is 4+.
化合物K0.91U1.79S6和KU2Se6是AAn2Q6锕系元素家族（A = 碱金属或铊；An = 钍或铀；Q = 硫、硒或碲）的成员，它们分别由US2、K2S和硫在1273 K下以及铀、K2Se和硒在1173 K下合成。KU2Se6在30 K以上表现出居里 - 外斯行为，在5 K以下没有磁有序。有效磁矩μ(eff)的值为2.95(1) μB/U。其电子光谱显示出5f - 5f跃迁的特征峰。它是一种半导体，导电的活化能为0.27 eV。K0.91U1.79S6和KU2Se6都结晶于正交晶系的空间群Immm，且具有KTh2Se6结构类型。两者都包含AAn2Q6家族特有的无限一维线性Q - Q链。在已知的AAn2Q6化合物中，典型的是，在KU2Se6中，有两个交替的Se - Se距离，分别为2.703(2) Å和2.855(2) Å，两者都比Se - Se单键长得多。相比之下，在K0.91U1.79S6中，这是该家族第一个进行结构表征的硫化物，有交替的正常S2(2-)对，长度为2.097(5) Å。在K0.91U1.79S6中，U的形式氧化态为4+。
