Department of Materials and Environmental Chemistry, Stockholm University, SE-106 91 Stockholm, Sweden.
Dalton Trans. 2013 Jun 28;42(24):8815-9. doi: 10.1039/c3dt50706h. Epub 2013 May 3.
A new chromium tellurite oxochloride, Cr3Te5O13Cl3, has been prepared by solid-state reaction and the crystal structure was determined by single crystal X-ray diffraction. The compound crystallizes in the non-centrosymmetric space group P2(1)2(1)2(1) with the unit cell a = 4.90180(10) Å, b = 17.3394(2) Å, c = 17.5405(2) Å, Z = 4, R1 = 0.0282. The Cr(3+) ions have octahedral [CrO6] oxygen coordination, the Te(4+) ions have one sided [TeO3] and [TeO3Cl] coordinations. The [CrO6] octahedra are edge sharing and form chains extending along [100]. These are connected by corner sharing [TeO3] and [TeO3Cl] groups to form layers parallel to (110). The layers are connected by weak interactions in between Te(4+) in the layers and Cl(-) ions located in between. The compound undergoes antiferromagnetic ordering at ~34 K with a Weiss constant of -230 K. Isothermal magnetization measurements reveal a critical field of about 0.25 T above which the magnetization versus field changes from linear to a Brillouin-like saturation behaviour. The frustration ratio amounts to ~6.8 indicative of sizable competing antiferromagnetic spin-exchange interaction. The dielectric constant ε (6 kHz) amounts to ~7.9 and decreases by about 1% on cooling from 50 K to liquid helium temperatures.
一种新的铬碲氧氯酸盐，Cr3Te5O13Cl3，通过固态反应合成，并通过单晶 X 射线衍射确定了晶体结构。该化合物在非中心对称空间群 P2(1)2(1)2(1)中结晶，晶胞参数为 a = 4.90180(10) Å, b = 17.3394(2) Å, c = 17.5405(2) Å, Z = 4, R1 = 0.0282。Cr(3+) 离子具有八面体 [CrO6] 氧配位，Te(4+) 离子具有单边 [TeO3] 和 [TeO3Cl] 配位。[CrO6] 八面体是边缘共享的，并形成沿 [100] 延伸的链。这些通过顶角共享 [TeO3] 和 [TeO3Cl] 基团连接形成平行于 (110) 的层。层之间通过层内 Te(4+) 和位于层之间的 Cl(-) 离子之间的弱相互作用连接。该化合物在 ~34 K 下经历反铁磁有序， Weiss 常数为-230 K。等温磁化测量表明，在约 0.25 T 的临界场以上，磁化与磁场的关系从线性变为布喇菲型饱和行为。挫折比约为 ~6.8，表明存在相当大的竞争反铁磁自旋交换相互作用。介电常数 ε（6 kHz）约为 ~7.9，并在从 50 K 冷却到液氦温度时降低约 1%。
