Preparation, Crystal Structures, and Properties of Rhenates with Multiple Re–Re Bonds: Ln2ReO5 (Ln=Sm, Eu, Gd), Ln3Re2O9 (Ln=Pr, Nd, Sm), and Ln4Re6O19 (Ln=La–Nd)
Preparation, Crystal Structures, and Properties of Rhenates with Multiple Re–Re Bonds: Ln2ReO5 (Ln=Sm, Eu, Gd), Ln3Re2O9 (Ln=Pr, Nd, Sm), and Ln4Re6O19 (Ln=La–Nd)
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具有多个 Re-Re 键的铼酸盐的制备、晶体结构和性能：Ln2ReO5 (Ln=Sm、Eu、Gd)、Ln3Re2O9 (Ln=Pr、Nd、Sm) 和 Ln4Re6O19 (Ln=La-Nd)
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
U. Rodewald
中科院分区：
文献类型：
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作者：
W. Jeitschko;D. Heumannskaemper;M. S. Schriewer;U. Rodewald
大多数标题化合物是由稀土偏过氧化氢配合物Ln（ReO 4）3与稀土金属在密封石英管中反应制得的。Nd 4 Re 6 O 19是由金属间化合物NdRe 2与偏高锰酸盐Nd（ReO 4）3反应得到的。通过四圆X射线衍射仪对Eu_2 Re_O_5孪晶的衍射数据[a=861.0（4）pm，c=574.3（3）pm]和对Gd_2 Re_O_5的衍射数据[a =858.8（4）pm，c=569.6（2）pm]进行了分析，确定了化合物Ln_2 Re_O_5的晶体结构为四方晶系（P4/n，Z=4）。Sm_3Re_2 O_9的单晶结构[P_1，a=551.8（1）pm，B=678.8（2）pm，c=1086.7（3）pm，α=76.57（1）°，β=75.56（2）°，γ=68.66（1）°]。稀土化合物Ln 4 Re 6 O 19的结构首次确定为La 4 Re 6 O 19。在化合物Ln 2 ReO 5中，氧化数为+4的Re原子与形式的Re-Re三键（225 pm）配对，形成正方形反棱柱氧配位（Re 2 O 8）。在Sm_3Re_2 O_9中存在两种Re_2对。具有形式三键的Re（IV）对的Re-Re距离再次为225 pm。它们位于氧原子的四棱柱中。其他的氧原子，氧化数为+5，具有八面体氧配位。它们通过它们的氧八面体的共同边缘形成对，具有242 pm的形式双键。这些化合物的磁性表明，这些化合物的磁性原子不携带任何实质性的磁矩。本文简要介绍了稀土氧化物的晶体结构。Re-Re键长与从氧化态推断的形式键级相关。
Most of the title compounds were prepared by reaction of the rare-earth metaperrhenates Ln(ReO4)3 with the rare-earth metals in sealed silica tubes. Nd4Re6O19 was obtained by reaction of the intermetallic compound NdRe2 with the metaperrhenate Nd(ReO4)3. The compounds Ln2ReO5 crystallize with a tetragonal structure (P4/n, Z=4), which was determined from four-circle X-ray diffractometer data of twinned crystals of Eu2ReO5 [a=861.0(4) pm, c=574.3(3) pm] and refined for Gd2ReO5 [a=858.8(4) pm, c=569.6(2) pm]. The compounds Ln3Re2O9 are isotypic with La3Re2O9, however, with somewhat differing oxygen coordination of the rare-earth atoms, as was shown by a structure refinement from single-crystal data of Sm3Re2O9 [P1, a=551.8(1) pm, b=678.8(2) pm, c=1086.7(3) pm, α=76.57(1)°, β=75.56(2)°, γ=68.66(1)°]. The rhenates Ln4Re6O19 have a structure first determined for La4Re6O19. The rhenium atoms in the compounds Ln2ReO5, with the oxidation number +4, are paired with a formal Re–Re triple bond (225 pm) in a square-antiprismatic oxygen coordination (Re2O8). In Sm3Re2O9 two kinds of Re2 pairs are present. The Re(IV) pairs with a formal triple bond have again a Re–Re distance of 225 pm. They are situated in a tetragonal prism of oxygen atoms. The other rhenium atoms, with oxidation number +5, have octahedral oxygen coordination. They form pairs via a common edge of their oxygen octahedra with a formal double bond of 242 pm. The magnetic properties of these compounds indicate that the rhenium atoms do not carry any substantial magnetic moments. The crystal structures of the reduced oxorhenates of the rare-earth elements are briefly reviewed. The Re–Re bond lengths correlate with the formal bond order deduced from the oxidation states.