The new mineral giacovazzoite, K 5 Fe 3+ 3 O(SO 4 ) 6 (H 2 O) 9 ·H 2 O, has been discovered in the Monte Arsiccio mine, Apuan Alps, Tuscany, Italy. It occurs as orange–brown prismatic crystals, up to 0.1 mm long, with yellowish streak and vitreous luster. It is brittle, with a perfect {100} cleavage. Associated minerals are alum-(K), gypsum, krausite, magnanelliite, and scordariite. Electron microprobe analysis (WDS mode) gave (in wt%): SO 3 45.82, Fe 2 O 3 22.67, K 2 O 22.72, H 2 O calc 17.18, total 108.39. The high total, after the addition of calculated H 2 O (based on structural results), is due to the dehydration of the sample during analysis. The corresponding empirical chemical formula, on the basis of 25 anions and 10 H 2 O groups, is K 5.06 Fe 3+ 2.98 O(SO 4 ) 6.00 ·10H 2 O. Giacovazzoite is monoclinic, space group P 2 1 /c , with unit-cell parameters a = 9.4797(2), b = 18.4454(5), c = 18.0540(4) Å, β = 92.626(2)°, V = 3153.55(13) Å 3 , Z = 4. Its crystal structure was refined to R 1 = 0.0587 for 10,254 reflections with F o > 4σ( F o ) and 511 refined parameters. It is formed by a structural unit, represented by a heteropolyhedral [Fe 3+ 3 O(SO 4 ) 6 (H 2 O) 3 ] 5− cluster, and an interstitial complex, having composition {K 5 (H 2 O) 7 } 5+ . The [Fe 3+ 3 O(SO 4 ) 6 (H 2 O) 3 ] 5− clusters form layers parallel to {100} which are bonded in this plane by K atoms. Successive layers are bonded, along c , through H-bonds, and by K atoms. The heteropolyhedral cluster occurring in giacovazzoite is known in the crystal structures of metavoltine, scordariite, carlsonite, and a series of synthetic compounds. Among them, the β-Maus’ salt has isotypic relationships with giacovazzoite. This latter mineral easily dehydrates and its dehydrated product has been investigated.

中文翻译：

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阿普安阿尔卑斯山（意大利托斯卡纳）硫酸盐的晶体化学。四、Gaacovazzoite，K5Fe3+3O(SO4)6(H2O)9·H2O，β-鼠盐的天然类似物及其脱水产物

在意大利托斯卡纳Apuan Alps 的Monte Arsiccio 矿中发现了新矿物钙镁石K 5 Fe 3+ 3 O(SO 4 ) 6 (H 2 O) 9 ·H 2 O。它以橙棕色棱柱状晶体出现，长达0.1毫米，具有淡黄色条纹和玻璃光泽。它很脆，具有完美的 {100} 解理。伴生矿物是明矾 (K)、石膏、克劳石、菱镁矿和辉绿岩。电子微探针分析（WDS 模式）给出（重量%）：SO 3 45.82、Fe 2 O 3 22.67、K 2 O 22.72、H 2 O calc 17.18，总计108.39。在添加计算出的 H 2 O（基于结构结果）后，高总量是由于样品在分析过程中脱水所致。基于25个阴离子和10个H 2 O基团，相应的经验化学式为K 5.06 Fe 3+ 2.98 O(SO 4 ) 6.00 ·10H 2 O。Giacovazzoite为单斜晶系，空间群为P 2 1 /c ，晶胞参数 a = 9.4797(2), b = 18.4454(5), c = 18.0540(4) Å, β = 92.626(2)°, V = 3153.55(13) Å 3 , Z = 4. 它的晶体对于 F o > 4σ( F o ) 和 511 个细化参数的 10,254 次反射，结构被细化为 R 1 = 0.0587。它由以杂多面体 [Fe 3+ 3 O(SO 4 ) 6 (H 2 O) 3 ] 5- 簇表示的结构单元和间隙复合物形成，其组成为{K 5 (H 2 O) 7 5+。[Fe 3+ 3 O(SO 4 ) 6 (H 2 O) 3 ] 5- 簇形成平行于{100}的层，其通过K原子在该平面内键合。沿 c 的连续层通过 H 键和 K 原子键合。杂多面体簇出现在辉石辉石中，在 metavoltine、烧锂辉石、Carlsonite 和一系列合成化合物的晶体结构中是已知的。他们之中，β-鼠盐与钙镁沸石具有同种关系。后一种矿物质容易脱水，并且已经研究了其脱水产物。