Disodium tetrafluoroargentate(II) (Na2AgF4) has been synthesized by the thermal decomposition of NaAg(III)F4 in the presence of NaF. This novel synthetic pathway yielded a high-purity product which enabled determination of the crystal structure and magnetic properties of this compound. The crystal structure of Na2AgF4 contains infinite [AgF2+4/2]2â chains, in analogy to β-K2AgF4, but with a different packing of chains. The unusually short Ag2+â¯Ag2+ contact of 3.342 Ã
within the chain is the shortest Ag2+â¯Ag2+ distance among all structurally characterized compounds of divalent silver. This structural feature is responsible for the 1D antiferromagnetic properties of Na2AgF4 as determined from powder magnetic susceptibility measurements. These findings are rationalized with the aid of calculations of magnetic coupling constants within the framework of the Density Functional Theory including on-site Coulomb repulsion (DFT+U).
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氟精
氨酸
钠(II)(Na2AgF4)是通过 NaAg(III)F4 在 NaF 存在下的热分解合成的。这一新颖的合成途径获得了高纯度的产品,从而得以确定该化合物的晶体结构和磁性能。Na2AgF4 的晶体结构包含无限的[AgF2+4/2]2â链,与 β-K2AgF4 类似,但链的堆积方式不同。链内的 Ag2+â¯Ag2+ 接触点异常短,只有 3.342 Ã,是所有具有结构特征的二价
银化合物中 Ag2+â¯Ag2+ 距离最短的。粉末磁感应强度测量结果表明,这一结构特征是 Na2AgF4 具有一维反
铁磁特性的原因。在包括现场库仑斥力(DFT+U)在内的密度泛函理论框架内对磁耦合常数进行计算后,这些发现变得更加合理。