Nickolayite, FeMoP, a new natural molybdenum phosphide

Abstract

Nickolayite, FeMoP, is a new terrestrial phosphide structurally related to allabogdanite (high-pressure modification of (Fe,Ni)2P), and the meteoritic phosphides florenskyite, FeTiP and andreyivanovite, FeCrP. From the point of view of chemical composition, nickolayite is an Fe-analogue of monipite, MoNiP. The mineral was discovered in the Daba-Siwaqa complex, Central Jordan, a part of the pyrometamorphic Hatrurim Formation (the Mottled Zone), whose outcrops encompass a 150 × 200 km area around the Dead Sea in the Middle East. Nickolayite appears as an accessory phase in the fused clinopyroxene–plagioclase rocks texturally resembling gabbro–dolerite. The irregularly shaped grains of the mineral, up to 80 μm in size are associated with baryte, tridymite, chromite, hematite, pyrrhotite, fluorapatite, titanite and powellite. Macroscopically, nickolayite grains possess light-grey to greyish-white colour and metallic lustre. The mineral is ductile. The mean VHN hardness (50 g load) is 538 kg mm–2. The calculated density based on the empirical formula and the unit-cell parameters is 7.819 g cm–1. In reflected light, nickolayite has a white colour, with no bireflectance or pleochroism. The COM approved reflectance values [Rmax/Rmin (%), λ(nm)] are: 48.5/46.5 (470), 50.5/48.5 (546), 51.8/49.9 (589) and 53.9/52.0 (650). The chemical composition of the holotype crystal is (electron microprobe, average of 4 analyses, wt.%): Fe 32.21, Mo 47.06, Ni 3.69, Co 0.13, P 17.45, total 100.54, that corresponds to the empirical formula Fe1.00(Mo0.87Ni0.11Fe0.02)Σ1.00P1.00 and an ideal formula of FeMoP. Nickolayite is orthorhombic, space group Pnma, unit-cell parameters of holotype material are: a = 5.9519(5), b = 3.7070(3), c = 6.8465(6) Å, V = 151.06(2) Å3 and Z = 4. The crystal structure of holotype material was solved and refined to R1 = 0.0174 based on 251 unique observed reflections. The origin of the mineral is probably connected to the processes of co-reduction of molybdenum- and phosphorus-bearing minerals during high-temperature pyrometamorphic processes.

Yakubovichite, CaNi2Fe3+(PO4)3, a new nickel phosphate mineral of non-meteoritic origin

“…1). In the type locality of yakubovichite -an abandoned phosphorite quarry in the Daba-Siwaqa complex, Transjordan Plateau, Jordan (31° 21' 52'' N, 36° 10' 55'' E), trevorite was found in clinopyroxene-plagioclase paralava containing phosphides -nickolayite, FeMoP (Murashko et al 2022) Bunsenite, a naturally occurring NiO, was discovered at Johanngeorgenstadt, Erzgebirge, Saxony, Germany, within the specific mineral assemblages formed by the "dry oxidation" of Ni arsenide ores of the Ag-Bi-Co-Ni-U formation (Bergemann 1858;Roberts et al 2001Roberts et al , 2004.…”

Deynekoite, Ca9□Fe3+(PO4)7 – a new mineral of the merrillite group from phosphide-bearing contact facies of paralava, Hatrurim Complex, Daba-Siwaqa, Jordan

“…The Hatrurim Complex is distributed along the Dead Sea rift as a series of outcrops of pyrometamorphic rocks in the territories of Israel, Palestine and Jordan (Bentor, 1960;Gross, 1977Gross, , 1984Vapnik et al, 2007;Novikov et al, 2013) (Galuskina et al, 2017a;Galuskin et al, , 2019Galuskin et al, , 2021Galuskin et al, , 2023a. In the Hatrurim Complex, molten rocks that are diverse in composition form veins, lenses and oval bodies of paralavas and slag-like rocks from a few centimetres to tens of metres in size (Galuskin et al, 2015;Galuskina et al, 2017aGaluskina et al, , 2017bGaluskina et al, , 2017cKrzątała et al, 2020;Krüger et al, 2021;Murashko et al, 2022). It is the paralavas, which feature relatively coarser-grained rocks compared to other types of pyrometamorphic rocks, that are associated with the discovery of a significant number of new minerals.…”

“…The phosphides discovered were transjordanite, Ni 2 P; zuktamrurite, FeP 2 ; murashkoite, FeP; orishchinite, Ni 2 P; and nickolayite, FeMoP. The phosphates were crocobelonite, CaFe 3+ (PO 4 )O; moabite, NiFe 3+ (PO 4 )O; yakubovichite, CaNi 2 Fe 3+ (PO 4 ) 3 ; and nazarchukite, Ca 2 NiFe 3+ 2 (PO 4 ) 4 (Britvin et al, 2019a(Britvin et al, , 2019b(Britvin et al, , 2020(Britvin et al, , 2021a(Britvin et al, , 2021b(Britvin et al, , 2022a(Britvin et al, , 2022b(Britvin et al, , 2023a(Britvin et al, , 2023bMurashko et al, 2022).…”

Discovery of terrestrial andreyivanovite, FeCrP, and the effect of Cr and V substitution on the low-pressure barringerite-allabogdanite transition

“…The Hatrurim Complex has recently become known as a source of terrestrial phosphides (Britvin et al 2015). Here, besides the phosphides typical of meteorites: schreibersite, Fe 3 P (Britvin et al 2021a), barringerite, Fe 2 P (Britvin et al 2017) and its high-pressure analogallobogdanite (Britvin et al 2021b), nine new phosphides: halamishite, Ni 5 P 4 (Britvin et al 2020a); negevite, NiP 2 (Britvin et al 2020b); nazarovite, Ni 12 P 5 (Britvin et al 2022a); zuktamrurite, FeP 2 (Britvin et al 2019a); transjoardanite, Ni 2 P (Britvin et al 2020c); polekhovskyite, MoNiP 2 (Britvin et al 2022b); murashkoite, FeP (Britvin et al 2019b); nickolayite, FeMoP (Murashko et al 2019); orishchinite, Ni 2 P (Britvin et al 2019c) were discovered. This detection of phosphides in the rocks of the Hatrurim Complex is unexpected.…”

“…Figure 7. Phase transitions trends in diagram barringerite-allabogdanite (according to Litasov et al 2020, with simplifications): 1 -experiment(Dera et al 2008); 2 -meteorite, crystallization from melt as a result of impact event(Britvin et al 2019); 3 -meteorite, barringeriteallabogdanite phase transition(Litasov et al 2020); 4 -paralava, formation of terrestrial allabogdanite after barringerite as a result of meteorite impact(Britvin et al 2021); 5 -paralava, barringerite -allabogdanite phase transition.…”