Majzlanite, K₂Na(ZnNa)Ca(SO₄)₄, a new anhydrous sulfate mineral with complex cation substitutions from Tolbachik volcano

Abstract

A new mineral majzlanite, ideally K2Na(ZnNa)Ca(SO4)4, was found in high-temperature exhalative mineral assemblages in the Yadovitaya fumarole, Second scoria cone of the Great Tolbachik Fissure Eruption (1975–1976), Tolbachik volcano, Kamchatka Peninsula, Russia. Majzlanite is associated closely with langbeinite and K-bearing thénardite. Majzlanite is grey with a bluish tint, has a white streak and vitreous lustre. The mineral is soluble in warm water. Majzlanite is monoclinic, C2/c, a = 16.007(2), b = 9.5239(11), c = 9.1182(10) Å, β = 94.828(7)°, V = 1385.2(3) Å3 and Z = 16. The eight strongest lines of the X-ray powder diffraction pattern are [d, Å (I, %)(hkl)]: 3.3721(40)($\bar{3}$12), 3.1473(56)($\bar{4}$02), 3.1062(65)($\bar{2}$22), 2.9495(50)($\bar{1}$31), 2.8736(100)($\bar{1}$13), 2.8350(70)(421), 2.8031(45)(511) and 2.6162(41)($\bar{5}$12). The following structural formula was obtained: K2Na(Zn0.88Na0.60Cu0.36Mg0.16)(Ca0.76Na0.24)(S0.98Al0.015Si0.005O4)4. The chemical composition determined by electron-microprobe analysis is (wt.%): Na2O 9.73, K2O 15.27, ZnO 11.20, CaO 7.03, CuO 4.26, MgO 1.07, Al2O3 0.47, SO3 51.34, SiO2 0.12, total 100.49. The empirical formula calculated on the basis of 16 O apfu is K1.99Na1.93Zn0.84Ca0.77Cu0.33Mg0.16(S3.94Al0.06Si0.01)O16 and the simplified formula is K2Na(Zn,Na,Cu,Mg)Σ2(Ca,Na)(SO4)4. No natural or synthetic compounds directly chemically and/or structurally related to majzlanite are known to date. The topology of the heteropolyhedral framework in majzlanite is complex. An interesting feature of the structure of majzlanite is an edge-sharing of ZnO6 octahedra with SO4 tetrahedra.

Third Worldwide Occurrence of Juangodoyite, Na2Cu(CO3)2, and Other Secondary Na, Cu, Mg, and Ca Minerals in the Fore-Sudetic Monocline (Lower Silesia, SW Poland)

“…The same is true for K-Cu pair, which is only confirmed in channels of aleutite [54]. A (Zn,Na,Cu,Mg) diadochy is also known in majzlanite [55]. Nevertheless, possible Na-Cu and K-Cu substitution systems in our minerals need further studies to be confirmed or disproved.…”

Anhydrous alkali copper sulfates – a promising playground for new Cu2+ oxide complexes: new Rb-analogues of fumarolic minerals.

“…A similarly short Cu-S distance of 2.593 Å is observed in chlorothionite, K 2 CuCl 2 (SO 4 ) (Giacovazzo et al, 1976) wherein the CuO 6 octahedron shares an edge with a SO 4 group. Edge sharing has also been recently observed in the complex Zn sulfate majzlanite, K 2 Na(ZnNa)Ca(SO 4 ) 4 (Siidra et al, 2020), with a Zn-S distance of 2.8704(4) Å.…”

Glikinite, Zn3O(SO4)2, a new anhydrous zinc oxysulfate mineral structurally based on OZn4 tetrahedra.

“…A zinc admixture is very common for many exhalative Cu sulfate minerals (Pekov et al ., 2018b). Surprisingly, until recently (Siidra et al ., 2018a,b; Siidra et al ., 2020), no anhydrous sulfate minerals with Zn-dominated sites in the structure were known and the occurrence of zinkosite, ZnSO 4 , is doubtful to date (Wildner and Giester, 1988).…”