Möhnite, (NH4)K2Na(SO4)2, a new guano mineral from Pabellón de Pica, Chile

Abstract

A b s t r a c t T h e n e w m i n e r a l m ö h n i t e , i d e a l l y (NH 4 )K 2 Na(SO 4 ) 2 , the ammonium analogue of aphthitalite, is found in a guano deposit on the Pabellón de Pica mountain, near Chanabaya, Iquique Province, Tarapacá Region, Chile. It is associated with salammoniac, halite, joanneumite, natroxalate, nitratine, chanabayaite, and a clay mineral. Möhnite occurs as random aggregates and clusters of brown imperfect bipyramidal or spindle-shaped crystals. The mineral is brittle, with Mohs' hardness of 3; D meas is 2.4(1) g/cm 3 and D calc is 2.461 g/cm 3 . The IR spectrum shows the presence of NH 4 + cations (the bands at 1431, 3076 and 3240 cm −1 ). Möhnite is almost isotropic, optically neutral; ε = ω = 1.505(2). The chemical composition (electron-microprobe data, N determined by gas chromatography of products of ignition, H calculated by stoichiometry, wt%) is: (NH 4 ) 2 O 7.99, Na 2 O 9.49, K 2 O 32.34, SO 3 51.32, total 101.14. The empirical formula is (NH 4 ) 0.95 Na 0.95 K 2.14 S 1.99 O 8 . The crystal structure was solved and refined to R=0.049 based on 241 unique reflections with I>2σ(I). Möhnite is trigonal, space group P 3 m1 , a=5.7402(3) Å, c=7.435(1) Å, V=212.16(4) Å 3 , Z=1. The strongest reflections of the powder X-ray diffraction pattern [d, Å (I,%) (hkl)] are: 4.955 (

Ammoniovoltaite, (NH4)2Fe2+5Fe3+3Al(SO4)12(H2O)18, a new mineral from the Severo-Kambalny geothermal field, Kamchatka, Russia

“…The majority of these minerals originates from: (1) volcanic activity (~29%) (Table 10); (2) guano decomposition (~25%) [e.g. möhnite (Chukanov et al ., 2015), niahite (Bridge and Robinson, 1983) and struvite (Maclvor, 1887; Yang et al ., 2014)]; and (3) black lignitic shales, burning coal seams or natural fires in oil-bearing shale (19%) [e.g. ammoniomagnesiovoltaite (Szakáll et al ., 2012), carlsonite and huizingite-(Al) (Kampf et al ., 2016)].…”

The stable isotope composition of nitrogen and carbon and elemental contents in modern and fossil seabird guano from Northern Chile – Marine sources and diagenetic effects

“…Crystalline organic compounds in modern and fossil guano are mainly water-insoluble uric acid, different crystalline phases of the phosphate and oxalate groups, and salts mainly halite from seawater and sal ammoniac [ 25 ]. Guano deposits are furthermore a source of rare minerals described in the mineralogical literature ([ 64 , 65 ] and references therein). We surveyed crystalline phases on selected powdered samples by XRD (X-ray Diffraction), using a Bruker D2 Phaser and PANanalyticals’ HighScore evaluation software at Technische Universität Berlin, FG Mineralogie.…”

Bojarite, Cu3(N3C2H2)3(OH)Cl2⋅6H2O, a new mineral species with a microporous metal–organic framework from the guano deposit at Pabellón de Pica, Iquique Province, Chile

“…The new mineral species bojarite, Cu 3 (N 3 C 2 H 2 ) 3 (OH)Cl 2 ⋅6H 2 O, described in this paper is the ninth new mineral species discovered in guano deposits at Pabellón de Pica, after ammineite CuCl 2 (NH 3 ) 2 (Bojar et al , 2010), joanneumite Cu(C 3 N 3 O 3 H 2 ) 2 (NH 3 ) 2 (Bojar et al , 2017), chanabayaite Cu 2 (N 3 C 2 H 2 ) 2 Cl(NH 3 ,Cl,H 2 O,□) 4 (Chukanov et al , 2015a), möhnite (NH 4 )K 2 Na(SO 4 ) 2 (Chukanov et al , 2015b), shilovite Cu(NH 3 ) 4 (NO 3 ) 2 (Chukanov et al , 2015c), antipinite KNa 3 Cu 2 (C 2 O 4 ) 4 (Chukanov et al , 2015d), triazolite NaCu 2 (N 3 C 2 H 2 ) 2 (NH 3 ) 2 Cl 3 ⋅4H 2 O (Zubkova et al , 2016; Chukanov et al , 2018) and ammoniotinsleyite (NH 4 ) 2 Al 2 (PO 4 ) 2 (OH)⋅2H 2 O (Chukanov et al , 2020a). All these minerals, except antipinite, contain nitrogen, most of them contain organic groups, and in seven new minerals from this locality Cu 2+ is a species-defining component.…”