During the last decades, layered structures have attracted particular and increasing interest due to the multitude of outstanding properties exhibited by their representatives. Particularly common among their archetypes, with a significant number of mineral and synthetic species structural derivatives, is that of litharge. In the current paper, we report the structural studies of two later rare-earth oxysulfates, [Ln₂O₂]SO₄ (Ln = Dy, Ho), which belong indeed to the grandreefite family, and a novel compound [Bi₂CuO₃]SO₄, which belongs to a new structure type and demonstrates the second example of Cu²⁺ incorporation into litharge-type slabs. Crystals of [Bi₂CuO₃]SO₄ were obtained under high-pressure/high-temperature (HP/HT) conditions, whereas polycrystalline samples of [Ln₂O₂]SO₄ (Ln = Dy, Ho) compounds were prepared via an exchange solid-state reaction. The crystal structure of [Bi₂CuO₃]SO₄ is based on alternation of continuous [Bi₂CuO₃]²⁺ layers of edge-sharing OBi₂Cu₂ and OBi₃Cu tetrahedra and sheets of sulfate groups. Cu²⁺ cations are in cis position in O5Bi₂Cu₂ and O6Bi₂Cu₂ oxocentered tetrahedra in litharge slab. The crystal structure of [Ln₂O₂]SO₄ (Ln = Dy, Ho) is completely analogous to those of grandreefite and oxysulfates of La, Sm, Eu, and Bi.

中文翻译：

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锂基硫酸盐矿物和合成化合物的扩展家族：[Bi2CuO3] SO4和[Ln2O2] SO4的制备和晶体结构（Ln = Dy和Ho）

在过去的几十年中，由于分层结构代表的众多杰出性能，分层结构引起了人们的特别关注和日益增长的兴趣。在它们的原型中，具有大量矿物和合成物种的结构衍生物的特别常见的是利特哈奇。在当前的论文中，我们报道了后来属于稀土元素的两种稀土氧硫酸盐[ Ln ₂ O ₂ ] SO ₄（Ln = Dy，Ho）和新型化合物[Bi ₂ CuO]的结构研究。₃ ] SO ₄，属于一种新的结构类型，并演示了Cu ²⁺的第二个例子掺入石渣型板中。在高压/高温（HP / HT）条件下获得了[Bi ₂ CuO ₃ ] SO _4的晶体，而通过[ Ln ₂ O ₂ ] SO ₄（Ln = Dy，Ho）化合物制备了多晶样品。交换固态反应。[Bi ₂ CuO ₃ ] SO ₄的晶体结构基于边缘共享的OBi ₂ Cu ₂和OBi ₃的连续[Bi ₂ CuO ₃ ] ²⁺层的交替铜四面体和片状硫酸盐基团。Cu ²⁺阳离子在石板中的O5Bi ₂ Cu ₂和O6Bi ₂ Cu ₂氧中心四面体中处于顺式位置。[ Ln ₂ O ₂ ] SO ₄（Ln = Dy，Ho）的晶体结构与La，Sm，Eu和Bi的大方铁矿和含氧硫酸盐的晶体结构完全相似。