New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India.
Inorg Chem. 2013 Sep 3;52(17):9741-8. doi: 10.1021/ic400369a. Epub 2013 Aug 21.
A new intermetallic compound Eu2AgGe3 has been synthesized using high-frequency induction heating method. Single-crystal X-ray diffraction data showed that Eu2AgGe3 crystallizes in the orthorhombic Ba2LiSi3 structure type, with Fddd space group and lattice parameters a = 8.7069(17) Å, b = 15.011(3) Å, c = 17.761(4) Å. Eu2AgGe3 is composed of infinite arrays of hexagonal [Ag3Ge3] units stacked along the [001] direction, and the Eu sites are sandwiched between these parallel hexagonal networks. Temperature-dependent powder XRD data and DTA hint toward a structural phase transition from orthorhombic to hexagonal above 477 K and an unusual reversible transition to the original phase, i.e., orthorhombic phase at around 718 K. Magnetic measurements on Eu2AgGe3 sample show paramagnetic behavior above 100 K and weak ferromagnetic interactions below 80 K. Mössbauer spectroscopy and X-ray absorption near-edge spectroscopic (XANES) studies reveal that Eu atoms in Eu2AgGe3 exist in the divalent oxidation state.
一种新的金属间化合物 Eu2AgGe3 已通过高频感应加热法合成。单晶 X 射线衍射数据表明，Eu2AgGe3 结晶为正交的 Ba2LiSi3 结构类型，属于 Fddd 空间群，晶格参数为 a = 8.7069(17) Å，b = 15.011(3) Å，c = 17.761(4) Å。Eu2AgGe3 由沿 [001] 方向堆叠的无限阵列的六角形 [Ag3Ge3] 单元组成，Eu 位被夹在这些平行的六方网络之间。粉末 XRD 数据和 DTA 的温度依赖性表明，在 477 K 以上存在从正交相到六方相的结构相变，并且在 718 K 左右存在异常的可逆相变，即返回到原始相，即正交相。Eu2AgGe3 样品的磁性测量表明，在 100 K 以上表现为顺磁行为，在 80 K 以下表现为弱铁磁相互作用。穆斯堡尔光谱和 X 射线吸收近边谱（XANES）研究表明，Eu2AgGe3 中的 Eu 原子处于二价氧化态。
