Crystal Structure of the Transition‐Metal Molybdates and Tungstates. V. Paramagnetic Alpha‐Nh2(MoO4)3
Crystal Structure of the Transition‐Metal Molybdates and Tungstates. V. Paramagnetic Alpha‐Nh2(MoO4)3
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V. 顺磁性α-Nh2(MoO4)3 过渡金属钼酸盐和钨酸盐的晶体结构。
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发表时间：
1969
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影响因子：
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通讯作者：
J. Bernstein
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作者：
P. B. Jamieson;S. Abrahams;J. Bernstein
顺磁性α-Nd 2（MoO 4）3在转变温度低于960°C时制备，以白钨矿结构的微妙变体结晶。四元晶系基本晶胞的晶格常数为a = 5.298 ± 0.007，c = 11.705 ± 0.023，空间群为I41/a，晶胞参数为43。两个Nd原子在每三个可用位置上的有序分布导致额外的弱散射，对应于a = 27.02，B = 11.705和c = 11.85 A，β = 105.3°，空间群C2的单斜晶胞。用PEXRAD测量了半径（sinθ）/ λ = 1.02 A−1的倒半球内2490个白钨矿样反射的积分强度，其中198个是独立的，高于背景。细化的原子位置，假设23 Nd的统计分布在每个白钨矿4 B网站，导致测量和计算的结构因子之间的协议因子为0.0375。每个Nd原子与8个氧原子配位，其中4个氧原子为十二面体。
Paramagnetic α‐Nd2(MoO4)3, prepared below the transition temperature of 960°C, crystallizes in a subtle variant of the scheelite structure. The lattice constants of the basic tetragonal unit cell are a = 5.298 ± 0.007 and c = 11.705 ± 0.023 A, with space group I41/a and 43 of a Nd2(MoO4)3 formula per unit cell. The ordered distribution of two Nd atoms over every three available sites results in additional weak scattering corresponding to a monoclinic unit cell with a = 27.02, b = 11.705, and c = 11.85 A, with β = 105.3°, space group C2. The integrated intensities of 2490 scheelitelike reflections within a reciprocal hemisphere of radius (sinθ) / λ = 1.02 A−1 were measured with PEXRAD, of which 198 were independent and above background. Refinement of the atomic positions, assuming a statistical distribution of 23 Nd on each scheelite 4b site, resulted in an agreement factor between measured and calculated structure factors of 0.0375. Each Nd atom is dodecahedrally coordinated to eight oxygen atoms, with fo...