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首页> 外文期刊>Zeitschrift fur Anorganische und Allgemeine Chemie >LuFSeO3 and LuClSeO3: Two non-isotypic halide oxoselenates(IV) of lutetium
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LuFSeO3 and LuClSeO3: Two non-isotypic halide oxoselenates(IV) of lutetium

机译:LuFSeO3 和 LuClSeO3:镥的两种非同型卤化物氧代硒酸盐 (IV)

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摘要

Despite the formal similarity of LuFSeO3 and LuClSeO3 both compounds show significant structural differences due to the different positions of the halide anions (X-) within the pentagonal bipyramids LuO5X2(9-). However, both oxoselenates(IV) have these pentagonal bipyramids as basic modules in common that are connected via O2- edges to (1)(infinity){(LuO4/2O1/1X2/2c)-O-e-X-t(4-)} chains. LuClSeO3 crystallizes orthorhombically in space group Pnma (no. 62; a = 714.63(7), b = 681.76(7) and c = 864.05(9) pm; Z = 4), The structure is isotypic to that one recently presented for ErClSeO3. With a single Cl- anion in each an apical and an equatorial position, the (1)(infinity){(LuO4/2O1/1Cl2/2c)-O-e-Cl-t(4-)} chains have to be inclined with an angle of about 54 degrees relative to each other to get connected alternately by common Cl- corners and bridging SeO3(2-) pyramids. In contrast to that, LuFSeO3 which crystallizes triclinically in space group P (1) over bar (no. 2; a = 644.85(6), b = 684.41(7), c = 427.98(4) pm, alpha = 94.063(5), beta = 96.484(5) and gamma 91.895(5)degrees; Z = 2) takes a structural motif already known from CsTmCl2SeO3. Owing to the apical position of both halide anions it is now possible to connect the (1)(infinity){(MO4/2O1/1Cl2/2c)-O-e-Cl-t(5-)} chains directly via discrete Psi-tetrahedral SeO3(2-) groups to (2)(infinity){(MCl2SeO3)(-)} layers. The same layers are present in LuFSeO3 and without the formal alkali-metal halide unit (CsCl) of the CsTmCl2SeO3-type compounds, the (2)(infinity){(LuF2SeO3)(-)} layers can also be connected directly by common F- corners to a three-dimensional array. Torch-sealed evacuated silica ampoules were used for the synthesis of both lutetium(III) halide oxoselenates(IV). For LuFSeO3 these vessels have been graphitized before to prevent them from oxosilicate-producing side-reactions with the applied fluoride. The synthesis of LuClSeO3 required Lu2O3 and SeO2 in a molar ratio of 1 : 6 with a surplus of an eutectic RbCl/LiCl mixture as fluxing agent and an annealing period of five weeks at a temperature of 500 degrees C, whereas Lu2O3, LuF3 and SeO2 (in a molar ratio of I : I : 3) with CsBr as flux were converted to LuFSeO3 at 750 degrees C within six days.
机译:尽管 LuF[SeO3] 和 LuCl[SeO3] 在形式上相似,但由于卤化物阴离子 (X-) 在五边形双锥体 [LuO5X2](9-) 内的位置不同,这两种化合物都显示出显着的结构差异。然而,两种氧代硒酸盐(IV)都具有这些五边形双锥体作为共同的基本模块,它们通过O2-边缘连接到(1)(无穷大){[(LuO4/2O1/1X2/2c)-O-e-X-t](4-)}链。LuCl[SeO3]在空间群Ponma(编号62;a = 714.63(7),b = 681.76(7)和c = 864.05(9) pm;Z = 4),该结构与最近提出的ErCl[SeO3]结构同型。在顶端和赤道位置各有一个Cl-阴离子时,(1)(无穷大){[(LuO4/2O1/1Cl2/2c)-O-e-Cl-t](4-)}链必须以约54度的角度相互倾斜,才能通过共同的Cl-角和桥接[SeO3](2-)金字塔交替连接。与此相反,LuF[SeO3]在空间群P(1)上以三斜晶系结晶(2号;a=644.85(6),b=684.41(7),c=427.98(4)pm,α=94.063(5),β=96.484(5)和γ91.895(5)度;Z = 2) 取 CsTmCl2[SeO3] 中已知的结构基序。由于两个卤化物阴离子的顶端位置,现在可以通过离散的 Psi-四面体 [SeO3](2-) 基团将 (1)(无穷大){[(MO4/2O1/1Cl2/2c)-O-e-Cl-t](5-)} 链直接连接到 (2)(无穷大){(MCl2[SeO3])(-)} 层。LuF[SeO3]中存在相同的层,并且没有CsTmCl2[SeO3]型化合物的形式碱金属卤化物单元(CsCl),(2)(无穷大){(LuF2[SeO3])(-)}层也可以通过共同的F-角直接连接到三维阵列。火炬密封的真空二氧化硅安瓿瓶用于合成卤化镥(III)氧硒酸盐(IV)。对于 LuF[SeO3],这些容器之前已被石墨化,以防止它们与所施加的氟化物发生产生氧硅酸盐的副反应。LuCl[SeO3]的合成需要Lu2O3和SeO2的摩尔比为1:6,并含有过量的共晶RbCl/LiCl混合物作为助熔剂,在500°C的温度下退火5周,而以CsBr为助熔剂的Lu2O3、LuF3和SeO2(摩尔比为I:I:3)在750°C下在6 d内转化为LuF[SeO3]。

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