CRYSTAL STRUCTURE OF ZINC HYDROXIDE NITRATE, ZN5(OH)8(NO3)2.2H2O
CRYSTAL STRUCTURE OF ZINC HYDROXIDE NITRATE, ZN5(OH)8(NO3)2.2H2O
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DOI：
10.1107/s0567740870003230
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发表时间：
1970-01-01
期刊：
影响因子：
--
通讯作者：
OSWALD, HR
中科院分区：
文献类型：
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作者：
STAHLIN, W;OSWALD, HR
氢氧化锌硝酸盐，Zns（OH）s（NO3）2.2 HzO，单斜晶系，a= 19.480（5），B= 6.238（1），c= 5.517（1）A，fl= 93-28 o（2），空间群C2/m，每个晶胞有两个分子式单元。结构由Patterson和Fourier合成确定。用最小二乘法进行了精化。491个观测到的Weissenberg反射的最终R值为6 - 4%。该结构的特征在于锌原子以3：2的比例以八面体和四面体配位出现。八面体的锌原子被六个OH基团包围，属于CdI~-型片层，缺少1/4的金属原子。四面体配位的锌原子位于空八面体的上方和下方。四面体由三个OH基团和一个水分子形成。硝酸根基团不直接参与金属原子的配位。平均四面体Zn-O距离为1.95 A，显著短于平均八面体Zn-O距离2.13 A。通过ZnO或Zn（OH）z与Zn（NO3）2水溶液反应，获得作为微晶粉末的碱式硝酸锌（Feitknecht，1933）。在60 ℃下，硝酸锌和尿素的均相溶液（两种浓度均为1摩尔）沉淀，可以生长单晶。
Zinc hydroxide nitrate, Zns (OH) s (NO3) 2.2 HzO, is monoclinic with a= 19.480 (5), b= 6.238 (1), c= 5.517 (1) A, fl= 93-28 o (2), space group C2/m, two formula units per cell. The structure has been deter-mined from Patterson and Fourier syntheses. The refinement was done by the method of least squares. The final R value for 491 observed Weissenberg reflexions was 6" 4%. The structure is characterized by zinc atoms occuring in both octahedral and tetrahedral coordination in the ratio 3: 2. The octahedral zinc atoms, surrounded by six OH groups, belong to a CdI~-type sheet with ¼ of the metal atoms missing. The tetrahedrally coordinated zinc atoms are located above and below the empty octahedra. The tetrahedra are formed by three OH groups and one water molecule. The nitrate group is not directly involved in the coordination of the metal atoms. The average tetrahedral Zn-O distance of 1.95 A is significantly shorter than the mean octahedral Zn-O distance of 2.13 A.Zinc hydroxide nitrate is obtained as a microcrystalline powder by reaction of ZnO or Zn (OH) z with aqueous Zn (NO3) 2 solutions (Feitknecht, 1933). Single crystals can be grown by precipitation from homogeneous so-lution of zinc nitrate with urea at 60 C (both concen-trations eg 1 molar).