Abstract—In the \({\text{Cu}}_{3}^{{2 + }}\)(T⁵⁺O₄)₂ (T = As, V or P) natural system arsenates are trimorphous (lammerite, lammerite-β, and unnamed triclinic Cu₃[(As,V)O₄]₂), as well as vanadates (mcbirneyite, pseudolyonsite, and borisenkoite), while phosphates are represented by a poorly studied lammerite-like Cu₃[(P,As)O₄]₂ phase. In active oxidizing-type fumaroles related to the Tolbachik volcano in Kamchatka, Russia, all these minerals crystallized at temperature no lower than 250°C. The crystal structure of natural triclinic Cu₃[(As,V)O₄]₂ was first studied on a single crystal from the Yadovitaya fumarole at Tolbachik; R = 4.89%. It is isostructural to stranskiite and mcbirneyite and crystallizes in the P-1 space group; the unit-cell parameters are: a = 5.0701(8), b = 5.4047(8), c = 6.3910(8) Å, α = 70.091(13), β = 86.828(12), γ = 68.399(15)°, V = 152.61(4) ų, and Z = 1. This paper also contains new data on mcbirneyite (its novel As-enriched variety is characterized), lammerite, and lammerite-β. Original and previously published materials on natural members of the Cu₃(T⁵⁺O₄)₂ system are summarized and isomorphism and other crystal chemical features of minerals belonging to this system are discussed in comparison with the data on related synthetic compounds.

摘要—在\（{\ text {Cu}} _ {3} ^ {{2 +}} \）（T ⁵⁺ O ₄）₂（T = As，V或P）中，自然砷酸盐是三态的（层晶石） ，蓝铁矿-β和未命名的三斜晶型Cu ₃ [（As，V）O ₄ ] ₂，以及钒酸盐（mcbneyneyite，pseudoononsite和borisenkoite），而磷酸盐则是由缺乏研究的类似蓝铜矿的Cu ₃ [[（ P，As）O ₄ ] ₂相。在与俄罗斯堪察加的托尔巴奇克火山有关的活性氧化型富马mar中，所有这些矿物均在不低于250°C的温度下结晶。天然三斜晶Cu ₃ [（As，V）O ₄ ] ₂的晶体结构首先是在托尔巴奇克（Tolbachik）的Yadovitaya fumarole单晶上研究的；R＝ 4.89％。它与方铁矿和镁水英石同构，并在P -1空间群中结晶。晶胞参数为：a = 5.0701（8），b = 5.4047（8），c = 6.3910（8）Å，α= 70.091（13），β= 86.828（12），γ= 68.399（15）° ，V = 152.61（4）³，和ž=1。本文还包含有关麦兜石（其富砷新品种的特征），蓝铁矿和lammerite-β的新数据。总结了关于Cu ₃（T ⁵⁺ O ₄）₂系统天然成员的原始材料和先前发表的材料，并与相关合成化合物的数据进行了比较，讨论了属于该系统的矿物的同构性和其他晶体化学特征。