The new mineral vasilseverginite, ideally Cu9O4(AsO4)2(SO4)2, was found in the Arsenatnaya fumarole at the second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. It is associated with tenorite, lammerite, stranskiite, lammerite-β, langbeinite, dolerophanite, sanidine, hematite, and gahnite. Vasilseverginite occurs as prismatic crystals up to 0.02 × 0.02 × 0.06 mm3 combined in groups or interrupted crusts up to 1 × 2 cm2 in area and up to 0.1 mm thick. It is transparent, bright green, with vitreous luster. Dcalc is 4.41 g·cm−3. Vasilseverginite is optically biaxial (–), α 1.816(5), β 1.870(5), γ 1.897(5), estimated 2V is 30(15)°. Chemical composition (wt%, electron-microprobe) is: CuO 64.03, ZnO 0.79, Fe2O3 0.25, P2O5 0.05, As2O5 20.83, SO3 14.92, total 100.87. The empirical formula calculated on O = 20 apfu is (Cu8.78Zn0.11Fe0.033+⁠)Σ8.92As1.98P0.01S2.03O20. Vasilseverginite is monoclinic, P21/n, a = 8.1131(4), b = 9.9182(4), c = 11.0225(5) Å, β = 110.855(2)°, V = 828.84(6) Å3, and Z = 2. The strongest reflections in the powder XRD pattern [d,Å(I)(hkl)] are: 7.13(41)(101), 5.99(70)(110, 111), 5.260(100)(101), 4.642(46)(111), 3.140(31)(031), 2.821(35)(023), 2.784(38)(132, 032), 2.597(35)(204), and 2.556(50) (231, 212). The crystal structure, solved using single-crystal X-ray diffraction data, R1 = 0.025, is based upon complex [O4Cu9]10+ layers parallel to (101) that are composed of edge- and corner-sharing (OCu4) tetrahedra. The topology is unprecedented in inorganic structural chemistry. The crystal structure can be considered a hybrid of the structures of popovite Cu5O2(AsO4)2 and dolerophanite Cu2O(SO4) according to the scheme Cu9O4(AsO4)2(SO4)2 = Cu5O2(AsO4)2 + 2Cu2O(SO4). The chemical hybridization does not result in a significant increase in chemical complexity of vasilseverginite compared to the sum of those of popovite and dolerophanite, whereas the structural hybridization leads to the doubling of structural information per unit cell. The mineral is named in memory of the outstanding Russian mineralogist, geologist, and chemist Vasiliy Mikhailovich Severgin (1765–1826).

中文翻译：

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硅钙铁矿，Cu9O4（AsO4）2（SO4）2，一种新型富马矿物，具有杂化结构，包含新型以阴离子为中心的四面体结构单元

在俄罗斯堪察加半岛的托尔巴奇克火山大托尔巴奇克裂隙爆发北部突破的第二个火山口锥体的Arsenatnaya fumarole中，发现了一种新的矿物硅钙铁矿，理想的是Cu9O4（AsO4）2（SO4）2。它与红铁矿，蓝铁矿，方铁矿，β-lammerite，兰贝纳石，白云石，山铁矿，赤铁矿和钠长石有关。硅钙铁矿以棱柱状晶体的形式出现，最大可达0.02×0.02×0.06 mm3的组合，或者是断续的地壳，面积最大为1×2 cm2，最大厚度为0.1 mm。它是透明的，鲜绿色的，具有玻璃光泽。Dcalc为4.41g·cm-3。硅钙铝石是光学双轴（–），α1.816（5），β1.870（5），γ1.897（5），估计2V为30（15）°。化学成分（wt％，电子-微探针）为：CuO 64.03，ZnO 0.79，Fe 2 O 3 0.25，P 2 O 5 0.05，As 2 O 5 20.83，SO 3 14.92，总计100.87。根据O = 20 apfu计算的经验公式为（Cu8.78Zn0.11Fe0.033 +⁠）Σ8.92As1.98P0.01S2.03O20。硅钙铁矿是单斜晶的，P21 / n，a = 8.1131（4），b = 9.9182（4），c = 11.0225（5）Å，β= 110.855（2）°，V = 828.84（6）Å3，Z = 2 。粉末XRD图谱中最强的反射[d，Å（I）（hkl）]为：7.13（41）（101），5.99（70）（110、111），5.260（100）（101），4.642（ 46）（111），3.140（31）（031），2.821（35）（023），2.784（38）（132、032），2.597（35）（204）和2.556（50）（231、212） 。使用单晶X射线衍射数据（R1 = 0.025）解析的晶体结构基于平行于（101）的[O4Cu9] 10+复合层，该层由边和角共享（OCu4）四面体组成。在无机结构化学中，这种拓扑结构是前所未有的。根据方案Cu9O4（AsO4）2（SO4）2 = Cu5O2（AsO4）2 + 2Cu2O（SO4），可以认为该晶体结构是磷橄榄石Cu5O2（AsO4）2和白云石Cu2O（SO4）结构的混合体。与杂硅钙石和白云石的总和相比，化学杂交不会使vasilseverginite的化学复杂性显着增加，而结构杂交导致每单位细胞的结构信息增加一倍。该矿物的命名是为了纪念杰出的俄罗斯矿物学家，地质学家和化学家Vasiliy Mikhailovich Severgin（1765–1826）。而结构杂交导致每个单位单元的结构信息加倍。该矿物的命名是为了纪念杰出的俄罗斯矿物学家，地质学家和化学家Vasiliy Mikhailovich Severgin（1765–1826）。而结构杂交导致每个单位单元的结构信息加倍。该矿物的命名是为了纪念杰出的俄罗斯矿物学家，地质学家和化学家Vasiliy Mikhailovich Severgin（1765–1826）。