采用熔融硼酸法合成了一种具有层状结构的新型水合稀土多硼酸盐,La[B_5O_8(OH)(H_2O)]NO_3·2H_2O,并利用单晶X射线衍射技术确定了它的结构.它属于单斜晶系,P21/n空间群.其基本构建单元(fundamental building block,简称FBB)是由三...
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采用熔融硼酸法合成了一种具有层状结构的新型水合稀土多硼酸盐,La[B_5O_8(OH)(H_2O)]NO_3·2H_2O,并利用单晶X射线衍射技术确定了它的结构.它属于单斜晶系,P21/n空间群.其基本构建单元(fundamental building block,简称FBB)是由三个BO4和两个BO3基团所构成的一个双三元环[B_5O_(10)]基团.结构中每一个FBB通过共顶点氧原子与周围四个同样的单元连接成具有九元环窗口的二维[B_5O_(10)]层,La3+位于九元环中心附近.[B_5O_(10)]层沿着b方向进行堆积,硝酸根离子和结构中部分结晶水分子位于相邻的[B_5O_(10)]层之间.
A two-dimensional layered manganese(II) pyrophosphate, 2[Mn3(P2O7)2(H2O)2] (1), has been synthesized hydrothermally. Its structure is determined by single-crystal X-ray diffraction analysis. Its structure is built up ...
详细信息
A two-dimensional layered manganese(II) pyrophosphate, 2[Mn3(P2O7)2(H2O)2] (1), has been synthesized hydrothermally. Its structure is determined by single-crystal X-ray diffraction analysis. Its structure is built up by MnO6 octahedra and P2O7 units, with ammonium NH4+ cations residing in the interlayer regions. The manganese pyrophosphate layer consists of infinite chains of cis and trans edge sharing MnO6 octahedra linked by P2O7 units. Magnetic susceptibility measurements show that this compound exhibits ferrimagnetic-like ordering below 3.2 K. Further study shows that there are two possible superexchange pathways via the oxygen anions in Mn2+ ions. Owing to the different bridging modes of O2-, the competition between ferromagnetic interactions and antiferromagnetic interactions in Mn2+ ions results in the ferrimagnetic behavior of 1.
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