Alkali chalkogenido metalates(II/III)

混合价硫原二(Q)高铁酸盐（II/III）阴离子（A=Na， K, Rb Cs； Q=S, Se, Te）的碱金属(A)盐是一类结构可变的化合物，它们是更复杂的系统的模型，例如氧化还原酶或铁基超导体。它们的晶体化学，最近被许多混合价富铁盐扩展（主要是通过使用还原合成策略），是基于边共享[FeQ4]四面体。在A[FeQ2]-A2[FeQ2]段的四面体连接和阴离子/晶体结构尤其多样化：一方面，发现了几种构象的边共享四面体链，这些构象取决于Fe(II):Fe（III）的比例和A阳离子。另一方面[仅在混合价高铁酸盐中]4Fe4S模拟四面体簇[Fe4Q8]作为特征构建块出现。通常，高铁酸盐（II/III）是Robin&Day III类的混合价化合物，其磁性由HS-Fe(2/3)+-离子的强反铁磁偶联决定。然而，磁矩[类似于纯高铁酸盐（II）和（III）中的磁矩]相对于预期的“仅自旋”值显着降低，特别是在凝聚的聚阴离子中。此外，新型钠盐Na7[Fe2S6]中的二聚体是非常罕见的例子之一，其电荷波动导致两个铁离子之间的铁磁耦合。在这些结构和磁性不同的混价高铁酸盐（II/III）的基础上，本项目的目的是合成具有两种不同阳离子M2+ (Mn, Co, Zn)和M3+ (Al, In)的新型碱硫属金属酸盐（II/III），确定其晶体结构并测量其磁性能。对于新获得的（和相关的）化合物，使用自旋极化FP-LAPW DFT带结构方法计算化学键。对这些含有异双金属多阴离子的盐的研究，其比例M(II):M（III）可以比高铁酸盐更容易调整，不仅可以模拟高铁酸盐（II/III）：该结构家族的混合锰酸盐/钛酸盐的第一个结果表明，沿A[MQ2]-A2[MQ2]段的晶体化学被[MQ4]四面体的组合边/角和纯边共享大大扩展。这种结构的多样性以及金属阳离子本身的变化（如d电子数、磁稀释、离子半径、M-Q键特征）导致了广泛的化学键和物理性质。对这些低维金属酸盐（II/III）阴离子的碱性盐的研究，以及与高铁酸盐和纯金属酸盐（II）和（III）的比较，可以提高对更复杂的混合价体系的键合和磁性的一般理解，例如上面提到的那些。

Alkali metal (A) salts of mixed-valent chalcogenido(Q) ferrate(II/III) anions (A=Na, K, Rb Cs; Q=S, Se, Te) are a structurally variable class of compounds, which are furthermore models for much complexer systems like e.g. redox enzymes or iron-based superconductors.Their crystal chemistry, which has been recentyl extended by many mixed-valent Fe-rich salts (mainly via using reductive synthetic strategies) is based on edge-sharing [FeQ4] tetrahedra. Particularly diverse are the tetrahedra connections and the anions/crystal structures along the section A[FeQ2]-A2[FeQ2]: At one hand, chains of edge-sharing tetrahedra in several conformations, which depend on the Fe(II):Fe(III) ratio and the A cations, are found. On the other hand [exclusively in mixed-valent ferrates] 4Fe4S analog tetrahedra clusters [Fe4Q8] occur as characteristic building blocks. Commonly, the ferrates(II/III) are mixed-valent compounds of Robin&Day class III, with magnetic properties determined by a strong antiferromagnetic coupling of the HS-Fe(2/3)+- ions. However, the magnetic moments [similar to those in pure ferrates(II) and (III)] are considerably decreased with respect to the expected 'spin-only' values, especially in the condensed polyanions. Additionally, the dimer in the new sodium salt Na7[Fe2S6] is one of the very rare examples, for which charge fluctuations result in a ferromagnetic coupling between the two Fe ions.Based on these structurally and magnectically diverse mixed-valent ferrate(II/III) salts, the aim of this project is to synthesize new alkali chalcogenido metallates(II/III) with two different cations M2+ (Mn, Co, Zn) and M3+ (Al, In), to determine their crystal structures and to measure their magnetic properties. For the newly obtained (and related) compounds, the chemical bonding is calculated using spin-polarized FP-LAPW DFT band structure methods.The investigation of these salts containing heterobimetallic polyanions, for which the ratio M(II):M(III) can be ajusted much easier than for the ferrates, does not only allow to mimic the ferrates(II/III): First results on mixed manganates/indates of this structure family show, that the crystal chemistry along the section A[MQ2]-A2[MQ2] is considerably extended by acombined edge/corner and a pure edges-sharing of [MQ4] tetrahedra. This structure diversity as well as the variation of the metal cations themselves (e.g. number of d electrons, magnetic dilution, ionic radii, M-Q bond character) results in a wide range of the chemical bonding and the physical properties. The investigation of these basic alkali salts with low(er)-dimensional metallate(II/III) anions and the comparison with the ferrates and the pure metallates(II) and (III), allows to improve the general understanding of the bonding and the magnetism also in much complexer mixed-valent systems, e.g. like those mentioned above.