Preparation of Low-Dimensional Cluster Materials: Synthesis, Structure, and Properties of A2Ti2Nb6Cl14O5 (A = K, Rb, Cs), a Series of One-Dimensi
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- 作者：Ekaterina V. Anokhina ; Thirumalai Duraisamy ; and Abdessadek Lachgar
- 刊名：Chemistry of Materials
- 出版年：2002
- 出版时间：October 2002
- 年：2002
- 卷：14
- 期：10
- 页码：4111 - 4117
- 全文大小：378K
- 年卷期：v.14,no.10(October 2002)
- ISSN：1520-5002
文摘
In the course of our systematic investigation of metal oxychloride systems aimed at thepreparation of low-dimensional compounds, a new series of niobium oxychloride clustercompounds, A2Ti2Nb6Cl14O5 (A = K, Rb, Cs), was obtained from stoichiometric amounts ofACl (A = K, Rb, Cs), Ti, Nb2O5, NbCl5, and Nb, heated at 750 
C. The crystal structures ofthe series were determined by single-crystal X-ray diffraction techniques. The compoundscrystallize in the monoclinic system, space group C2/c, with unit cell parameters a = 21.503(3) Å, b = 8.816(1) Å, c = 15.710(2) Å, 
= 116.21(1), V = 2672.1(6) Å3, and Z = 4 for A =Rb. The full-matrix least-squares refinement against F 2 converged to R1 = 0.043 (Fo > 4
(Fo))and wR2 = 0.089 (all data for A = Rb). The crystal structure of A2Ti2Nb6Cl14O5 has one-dimensional character. It is based on chains formed by (Nb6
)
octahedral niobiumclusters connected to each other through apical chloride ligands and titanium counterions.The chains are held together by alkali metal cations. Intracluster bond distances analysisindicates that the cluster has 14 valence electrons. Magnetic susceptibility study showsparamagnetic behavior with a magnetic moment of 2.17 
B per formula unit for two unpairedelectrons contributed by two Ti3+.
C. The crystal structures ofthe series were determined by single-crystal X-ray diffraction techniques. The compoundscrystallize in the monoclinic system, space group C2/c, with unit cell parameters a = 21.503(3) Å, b = 8.816(1) Å, c = 15.710(2) Å, = 116.21(1), V = 2672.1(6) Å3, and Z = 4 for A =Rb. The full-matrix least-squares refinement against F 2 converged to R1 = 0.043 (Fo > 4(Fo))and wR2 = 0.089 (all data for A = Rb). The crystal structure of A2Ti2Nb6Cl14O5 has one-dimensional character. It is based on chains formed by (Nb6 ) octahedral niobiumclusters connected to each other through apical chloride ligands and titanium counterions.The chains are held together by alkali metal cations. Intracluster bond distances analysisindicates that the cluster has 14 valence electrons. Magnetic susceptibility study showsparamagnetic behavior with a magnetic moment of 2.17 B per formula unit for two unpairedelectrons contributed by two Ti3+.