Xia Sheng-qing, Bobev Svilen
Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA.
Chem Asian J. 2007 May 4;2(5):619-24. doi: 10.1002/asia.200700016.
A new transition-metal-containing Zintl phase, Eu(10)Cd(6)Bi(12), was synthesized by combining the elements in excess molten Cd. Single-crystal X-ray diffraction studies indicated that this compound crystallizes in the orthorhombic space group Cmmm (No. 65) with a=7.840(2), b=24.060(7), and c=4.7809(14) A. The crystal structure of Eu(10)Cd(6)Bi(12) can be viewed as a stacking of a series of [Cd(6)Bi(12)] double layers, which are arranged alternately along the b axial direction. The layers are composed of corner- and edge-shared CdBi(4) tetrahedra, a common feature in the crystal chemistry of many transition-metal Zintl phases. Electronic-band-structure calculations confirm the closed-shell configuration of all constituent elements and corroborate the electron count inferred by the Zintl formalism, that is, Eu(2+)Cd(2+)Bi(3-)Bi(2-). Magnetic-susceptibility measurements confirm the divalency of europium and show the existence of a long-range antiferromagnetic order of the Eu spins below 12.3 K.
通过在过量的熔融镉中混合各元素，合成了一种新型含过渡金属的津特耳相Eu(10)Cd(6)Bi(12)。单晶X射线衍射研究表明，该化合物结晶于正交空间群Cmmm（编号65），a = 7.840(2) Å，b = 24.060(7) Å，c = 4.7809(14) Å。Eu(10)Cd(6)Bi(12)的晶体结构可视为一系列[Cd(6)Bi(12)]双层的堆叠，这些双层沿b轴方向交替排列。这些层由角共享和边共享的CdBi(4)四面体组成，这是许多过渡金属津特耳相晶体化学中的一个共同特征。电子能带结构计算证实了所有组成元素的闭壳层构型，并证实了由津特耳形式主义推断的电子数，即Eu(2+)Cd(2+)Bi(3-)Bi(2-)。磁化率测量证实了铕的二价性，并表明在12.3 K以下存在Eu自旋的长程反铁磁有序。
