ADRANOSITE-(Fe), (NH4)(4)NaFe2(SO4)(4)Cl(OH)(2), A NEW AMMONIUM SULFATE CHLORIDE FROM LA FOSSA CRATER, VULCANO, AEOLIAN ISLANDS, ITALY

作者：Mitolo Donatella; Demartin Francesco^*; Garavelli Anna; Campostrini Italo; Pinto Daniela; Gramaccioli Carlo Maria; Acquafredda Pasquale; Kolitsch Uwe

来源：The Canadian Mineralogist, 2013, 51(1): 57-66.

DOI：10.3749/canmin.51.1.57

• adranosite-(Fe)
• new mineral species
• sublimates
• fumaroles
• crystal structure
• ammonium sulfates
• Vulcano
• Aeolian Islands
• Italy
• Anna Mine

The new mineral adranosite-(Fe), ideally (NH4)(4)NaFe2(SO4)(4)Cl(OH)(2), is the Fe3+-analogue of adranosite. It was found on a pyroclastic breccia in two different fumaroles at %26quot;La Fossa%26quot; crater of Vulcano, Aeolian Islands, Italy, and corresponds to an anthropogenic product previously observed in a burning coal dump at the Anna mine, near Aachen, Germany. The mineral is tetragonal, space group I4(1)/acd (no. 142), with a = 18.261(2), c = 11.562(1) angstrom, V = 3855.5(7) angstrom(3) (single-crystal data), and Z = 8. The six strongest reflections in the X-ray powder diffraction pattern are [d(obs) in angstrom(I)(hkl)]: 9.134(100)(020), 4.569(83)(040), 3.047(79)(152), 6.462(36)(220), 3.232(29)(251), and 2.891(11)(004). The average chemical composition of the holotype is (wt.%): Na2O 5.01, Fe2O3 15.77, Al2O3 5.11, K2O 0.82, (NH4)(2)O 15.76, SO3 50.96, Cl 3.71, H2O 2.75, -O Cl -0.84, total 99.05; the corresponding empirical formula is: [(NH4)(3.89)K-0.11](Sigma 4.00)Na-1.04[Fe1.27Al0.64](Sigma 1.91)S4.10O16.40Cl0.67(OH)(1.96). Adranosite-(Fe) forms aggregates of pale yellow acicular crystals up to 1 mm in length, the most common forms most probably being {100}, {110}, and {111}. The measured density is 2.18(1) g/cm(3), and the calculated density is 2.195 g/cm(3). Adranosite-(Fe) is uniaxial (-) with omega = 1.58(1), epsilon = 1.57(1) (lambda = 589 nm). Using single-crystal X-ray diffraction data from the holotype, the structure was refined to a final R(F) = 0.0415 for 670 independent observed reflections [I %26gt; 2 sigma(I)]. Adranosite-(Fe) is isostructural with its Al-analogue adranosite and contains NaO4Cl2 square tetragonal bipyramids, linked through their opposite Cl corners and helicoidal chains with composition [FeO4(OH)(2)SO4](n), both extending along [001]. The framework resulting from the sharing of the sulfate ions between the different chains displays cages in which the nine-coordinated hydrogen-bonded NH4+ ions are hosted.

• 出版日期2013-2