Sergey N. Britvin

Allabogdanite, (Fe, Ni)2P, a new mineral from the Onello meteorite: The occurrence and crystal structure

Abstract Allabogdanite, (Fe,Ni)2P, is a new mineral from the Onello iron meteorite (Ni-rich ataxite). It occurs as thin lamellar crystals disseminated in plessite. Associated minerals are nickelphosphide, schreibersite, awaruite, and graphite. Crystals of the mineral, up to 0.4 × 0.1 × 0.01 mm, are flattened on (001) with dominant {001} faces, and other faces that are probably {110} and {100}. Mirror twinning resembling that of gypsum is common, with possible twin composition plane {110}. Crystals are light straw-yellow with bright metallic luster. Polished (001) sections look silverywhite against an epoxy background. In reflected light in air, the mineral has a creamy color, with distinct anisotropy from light to dark creamy tint. No bireflectance was observed. R1/R2 (λ, nm) in air: 48.4/37.2(440), 46.7/36.8(460), 47.0/37.6(480), 47.5/38.1(500), 47.6/38.8(520), 48.2/39.2(540), 49.0/39.9(560), 49.6/40.7(580), 50.1/41.6(600), 50.5/41.9(620), 51.9/43.0(640), 52.3/44.3(660), 53.3/ 45.0(680), 54.4/46.2(700). No cleavage or parting was observed. Moh’s hardness is 5-6; the mineral is very brittle, and its calculated density 7.10 g/cm3. Its chemical composition (determined by microprobe methods, average of nine analyses) is: Fe 57.7, Ni 20.7, Co 1.4, P 20.4, Total 100.2 wt%, corresponding to (Fe1.51Ni0.50Co0.03)2.04P0.96 (three atoms per formula unit). Crystal structure: R1 = 0.040 for 138 unique observed (|Fo|≥ 4σF) reflections. Orthorhombic, Pnma, unit-cell parameters refined from powder data: a = 5.748(2), b = 3.548(1), c = 6.661(2) Å, V = 135.8(1), Å3, Z = 4; unitcell parameters refined from single-crystal data: a = 5.792(7), b = 3.564(4), c = 6.691(8) Å, and V = 138.1(3) Å3. Strongest reflections in the X-ray powder diffraction pattern are [d in Å, (I) (hkl)]: 2.238(100)(112), 2.120(80)(211), 2.073(70)(103), 1.884(50)(013), 1.843(40)(301), 1.788(40)(113), 1.774(40)(020). The mineral is named for Alla Bogdanova, Geological Institute, Kola Science Centre of Russian Academy of Sciences

Shulamitite Ca3TiFe3+AlO8 – a new perovskite-related mineral from Hatrurim Basin, Israel

Shulamitite, ideally Ca 3 TiFe 3+ AlO 8 , is a mineral intermediate between perovskite CaTiO 3 and brownmillerite Ca 2 (Fe,Al) 2 O 5 . It was discovered as a major mineral in a high-temperature larnite-mayenite rock from the Hatrurim Basin, Israel. Shulamitite is associated with larnite, F-rich mayenite, Cr-containing spinel, ye9elimite, fluorapatite, and magnesioferrite, and retrograde phases (portlandite, hematite, hillebrandite, afwillite, foshagite and katoite). The mineral forms reddish brown subhedral grains or prismatic platelets up to 200 μm and intergrowths up to 500 μm. The empirical formula of the holotype shulamitite (mean of 73 analyses) is (Ca 2.992 Sr 0.007 LREE 0.007 )(Ti 0.981 Zr 0.014 Nb 0.001 )(Fe 3+ 0.947 Mg 0.022 Cr 0.012 Fe 2+ 0.012 Mn 0.001 )(Al 0.658 Fe 3+ 0.288 Si 0.054 )O 8 . The X-ray diffraction powder-pattern (Mo Kα -radiation) shows the strongest lines {d [A]( I obs )} at: 2.677(100), 2.755(40), 1.940(40), 11.12(19), 1.585(17), 1.842(16), 1.559(16), 3.89 (13), 1.527(13). The unit-cell parameters and space group are: a = 5.4200(6), b = 11.064(1), c = 5.5383(7) A, V= 332.12(1) A 3 , Pmma, Z = 2. The calculated density is 3.84 g/cm 3 . The crystal structure of shulamitite has been refined from X-ray single-crystal data to R 1 = 0.029 %. No partitioning among octahedral sites was found for Ti and Fe 3+ in the structure of shulamitite, these cations are randomly distributed among all octahedra indicating an example of “valency-imposed double site occupancy”. The strong bands in the Raman spectrum of shulamitite are at: 238,250, 388,561, and 742 cm −1 . Shulamitite from the Hatrurim Basin crystallized under combustion metamorphism conditions characterized by very high temperatures (1150−1170 °C) and low pressures (high- T -region of the spurrite-merwinite facies). Chemical data for shulamitite and its Fe-analog from other metacarbonate occurrences (natural and anthropogenic) are given here.

Layered Hydrazinium Titanate: Advanced Reductive Adsorbent and Chemical Toolkit for Design of Titanium Dioxide Nanomaterials

LHT-9, a layered hydrazinium titanate with an interlayer spacing of ~9 Å, is a new nanohybrid compound combining the redox functionality of hydrazine, the ion-exchange properties of layered titanate, the large surface area of quasi-two-dimensional crystallites, surface Brønsted acidity, and the occurrence of surface titanyl bonds. LHT-9, ideally formulated as (N(2)H(5))(1/2)Ti(1.87)O(4), relates to a family of lepidocrocite-type titanates. It possesses a high uptake capacity of ~50 elements of the periodic table. Irreversibility of reductive adsorption allows LHT-9 to be used for cumulative extraction of reducible moieties (noble metals, chromate, mercury, etc.) from industrial solutions and wastewaters. Unlike sodium titanates that do not tolerate an acidic environment, LHT-9 is capable of uptake of transition metals and lanthanides at pH > 3. Adsorption products loaded with the desired elements retain their layered structures and can be used as precursors for tailored titanium dioxide nanomaterials. In this respect, the uptake of metal ions by LHT-9 can be considered as a method complementary to electrostatic self-assembly deposition (ESD) and layer-by-layer self-assembly (LBL) techniques. LHT-9 is readily synthesized in one step by a mild fluoride route involving hydrazine-induced hydrolysis of hexafluorotitanic acid under near-ambient conditions.

Earth's Phosphides in Levant and insights into the source of Archean prebiotic phosphorus

Natural phosphides - the minerals containing phosphorus in a redox state lower than zero – are common constituents of meteorites but virtually unknown on the Earth. Herein we present the first rich occurrence of iron-nickel phosphides of terrestrial origin. Phosphide-bearing rocks are exposed in three localities in the surroundings of the Dead Sea, Levant: in the northern Negev Desert, Israel and Transjordan Plateau, south of Amman, Jordan. Seven minerals from the ternary Fe-Ni-P system have been identified with five of them, NiP2, Ni5P4, Ni2P, FeP and FeP2, previously unknown in nature. The results of the present study could provide a new insight on the terrestrial origin of natural phosphides – the most likely source of reactive prebiotic phosphorus at the times of the early Earth.

Hatertite, Na2(Ca, Na)(Fe3+, Cu)2(AsO4)3, a new alluaudite-group mineral from Tolbachik fumaroles, Kamchatka peninsula, Russia

Hatertite, ideally Na 2 (Ca, Na)(Fe 3+ , Cu) 2 (AsO 4 ) 3 , was found in a fumarole of the North Breach of the Great fissure Tolbachik volcano eruption (1975–1976), Kamchatka Peninsula, Russia. The mineral occurs as individual, prismatic and tabular, honey-yellow crystals up to 0.3 mm across. It has a vitreous luster and yellow streak. Hatertite is monoclinic, C 2/ c , a = 12.590(2), b = 12.993(3), c =6.700(2) A, β =113.72(2)°, V = 1003.4(3) A 3 , Z =4, D calc = 4.06 g/cm 3 . The eight strongest lines of the powder X-ray diffraction pattern are [ d obs in A ( I ) ( hkl )]: 6.493(25)(020); 3.628 (25)(131); 3.204(39)( 112,131); 3.065(18)(002); 2.976(28)(312, 222); 2.830(100)(240), 2.632(36)(132); 1.647(19)(204,640). Hatertite is optically positive, α = 1.820(3), β = 1.825(3), γ = 1.833(3), 2V meas. = 60(10)°, 2V calc. = 77°. The orientation is Y = b . The chemical composition determined by the electron-microprobe analysis is as follows (wt.%): Na 2 O 8.49, K 2 O 2.41, MnO 1.64, CaO 7.06, Fe 2 O 3 11.15, ZnO 2.05, CuO 8.10, Al 2 O 3 2.22, As 2 O 5 55.67, total 98.79. The empirical formula (based on 12 O apfu ) is (Na 0.47 K 0.32 )(Na 0.84 Ca 0.16 ) (Ca 0.62 Na 0.19 Zn 0.16 Mn 0.14 ) (Fe 3+ 0.44 Cu 0.32 Al 0.13 Na 0.11 ) 2 (As 1.01 O 4 ) 3 . A general crystal chemical formula for hatertite should be written as NaNa(Ca 1−x M + x )(Fe 3+ 1+x M 2+ 1−x )(AsO 4 ) 3 , where 0.5 > x >0, M + is an unspecified monovalent cation, and M 2+ is an unspecified divalent cation. The crystal structure was solved by direct methods and refined to an agreement index R 1 = 0.028 on the basis of 751 independent observed reflections. Hatertite is a new arsenate member of the alluaudite group. Its structure is based upon chains of edge-sharing octahedra running along [−101] and linked by T (2)O 4 tetrahedra into layers parallel to (010). The layers are further interlinked through T (1)O 4 tetrahedra to form a three-dimensional octahedral-tetrahedral framework with the A (1) and A (2)’ sites in the interstices. The mineral was named in honor of Prof. Frederic Hatert (b. 1973), University of Liege, Belgium, for his contributions to the mineralogy and crystal chemistry of alluaudite-group minerals.

Alumoåkermanite, (Ca,Na)₂(Al,Mg,Fe²⁺)(Si₂O₇), a new mineral from the active carbonatite-nephelinite-phonolite volcano Oldoinyo Lengai, northern Tanzania

Abstract Alumoåkermanite, (Ca,Na)2(Al,Mg,Fe2+)(Si2O7), is a new mineral member of the melilite group from the active carbonatite-nephelinite-phonolite volcano Oldoinyo Lengai, Tanzania. The mineral occurs as tabular phenocrysts and microphenocrysts in melilite-nephelinitic ashes and lapilli-tuffs. Alumoåkermanite is light brown in colour; it is transparent, with a vitreous lustre and the streak is white. Cleavages or partings are not observed. The mineral is brittle with an uneven fracture. The measured density is 2.96(2) g/cm3. The Mohs hardness is ~4.5−6. Alumoåkermanite is uniaxial (−) with ω = 1.635(1) and e = 1.624−1.626(1). In a 30 mm thin section (+N), the mineral has a yellow to orange interference colour, straight extinction and positive elongation, and is nonpleochroic. The average chemical formula of the mineral derived from electron microprobe analyses is: (Ca1.48Na0.50Sr0.02K0.01)∑2.01(Al0.44Mg0.30Fe2+0.17Fe3+0.07Mn0.01)∑0.99(Si1.99Al0.01O7). Alumoåkermanite is tetragonal, space group P4̅. 21m with a = 7.7661(4) Å, c = 5.0297(4) Å, V = 303.4(1) Å3 and Z = 2. The five strongest powder-diffraction lines [d in Å, (I/Io), hkl] are: 3.712, (13), (111); 3.075, (25), (201); 2.859, (100), (211); 2.456, (32), (311); 1.757, (19), (312). Single-crystal structure refinement (R1= 0.018) revealed structure topology typical of the melilite-group minerals, i.e. tetrahedral [(Al,Mg)(Si2O7)] sheets interleaved with layers of (CaNa) cations. The name reflects the chemical composition of the mineral.

Water-Soluble Phosphine Capable of Dissolving Elemental Gold: The Missing Link between 1,3,5-Triaza-7-phosphaadamantane (PTA) and Verkade’s Ephemeral Ligand

We herein describe a tricyclic phosphine with previously unreported tris(homoadamantane) cage architecture. That water-soluble, air- and thermally stable ligand, 1,4,7-triaza-9-phosphatricyclo[5.3.2.1(4,9)]tridecane (hereinafter referred to as CAP) exhibits unusual chemical behavior toward gold and gold compounds: it readily reduces Au(III) to Au(0), promotes oxidative dissolution of nanocrystalline gold(0) with the formation of water-soluble trigonal CAP-Au(I) complexes, and displaces cyanide from [Au(CN)2](-) affording triangular [Au(CAP)3](+) cation. From the stereochemical point of view, CAP can be regarded as an intermediate between 1,3,5-triaza-7-phosphaadamantane (PTA) and very unstable aminophosphine synthesized by Verkades group: hexahydro-2a,4a,6a-triaza-6b-phosphacyclopenta[cd]pentalene. The chemical properties of CAP are likely related to its anomalous stereoelectronic profile: combination of strong electron-donating power (Tolmans electronic parameter 2056.8 cm(-1)) with the low steric demand (cone angle of 109°). CAP can be considered as macrocyclic counterpart of PTA with the electron-donating power approaching that of strongest known phosphine electron donors such as P(t-Bu)3 and PCy3. Therefore, CAP as sterically undemanding and electron-rich ligand populates the empty field on the stereoelectronic map of phosphine ligands: the niche between the classic tertiary phosphines and the sterically undemanding aminophosphines.

Rudashevskyite, the Fe-dominant analogue of sphalerite, a new mineral: Description and crystal structure

Abstract Rudashevskyite, Fe-dominant analogue of sphalerite, is an accessory phase in the Indarch meteorite (enstatite chondrite, EH4). It occurs as xenomorphic polycrystalline grains, 5-120 μm in size, associated with clinoenstatite, kamacite, troilite, oldhamite, niningerite, schreibersite, and roedderite. Macroscopically, rudashevskyite is black with resinous luster. In reflected light, it is gray with brownish tint. Isotropic, no internal reflections. Reflectance in air (%, λ): 19.5(400), 19.5(420), 19.5(440), 19.5(460), 19.6(470), 19.8(480), 19.8(500), 19.9(520), 20.2(540), 20.3(546), 20.5(560), 20.7(580), 20.8(589), 20.9(600), 20.9(620), 21.1(640), 21.1(650), 21.1(660), 21.1(680), and 21.2(700). Brittle. Dc 3.79 g/cm3. VHN 353 kg/mm2. Chemical composition (electron microprobe, average of 31 analyses on 11 grains, wt%): Fe 37.1, Zn 24.7, Mn 2.4, Cu 0.4, S 35.3, total 99.9. Empirical formula (2 apfu): (Fe0.61Zn0.35Mn0.04Cu0.01)Σ=1.00S1.00, ideally (Fe,Zn)S. Cubic, F-4̄3m, a 5.426(2) Å, V 159.8 (2) Å3, Z = 4. X-ray powder diffraction pattern (Debye-Scherrer, FeKα), [d(I)(hkl)]: 3.130(100)(111), 2.714(10)(200), 1.919(50)(220), 1.634(40)(311), 1.359(5)(400), 1.246(30)(331), 1.107(30)(422), 1.045(30)(511, 333). Crystal structure: R1 = 0.050 for 26 unique observed (|Fo| ≥ 4σF) reflections. It is named in honor for N.S. Rudashevsky, St. Petersburg, Russia, for his contributions to the study of ore minerals.

Lammerite-β, Cu3(AsO4)2, a new mineral from fumaroles of the Great Fissure Tolbachik eruption, Kamchatka Peninsula, Russia

Lammerite-β, Cu3(AsO4)2, occurs as a product of the post-eruption fumarole activity of the second cinder cone of the North breach of the Great Fissure Tolbachik eruption in 1975–1976, Kamchatka Peninsula, Russia. Sporadic light to dark green splinter-shaped grains are no larger than 0.15 mm in size. Cleavage is not observed. The mechanical admixture of finely dispersed hematite forms condensed brownish spots that are occasionally zonal relative to the contours of the lammerite-β grains. Associated minerals are euchlorine, piypite, alumoklyuchevskite, alarsite, and lammerite. Lammerite-β is brittle and transparent and has vitreous luster. The calculated density is 5.06 g/cm3. The mineral is not pleochroic, biaxial (+), α = 1.887(5), β = 1.936(5), γ = 2.01(1), 2V(calc.) = 80.9°; dispersion is strong, r < v. The new mineral is monoclinic, the space group is P21/c, a = 6.306(1), b = 8.643(1), c = 11.310(1) Å, β = 92.26(1)°, V = 615.9(1) Å3, and Z = 4. Characteristic reflections in the X-ray powder diffraction pattern (I-d-hkl) are 100-2.83-004, 10-5.65-002, and 10-4.32-020. The chemical composition is as follows, wt %: 51.30 CuO, 0.32 ZnO, 49.12 As2O3, with a total of 100.74 wt %. The empirical and idealized formulas are Cu3.00Zn0.02As1.99O8 and Cu3(AsO4)2, respectively.

Crystal structure of rimkorolgite, Ba[Mg5(H2O)7(PO4)4](H2O), and its comparison with bakhchisaraitsevite

The crystal structure of rimkorolgite, ideally Ba[Mg 5 (H 2 O) 7 (PO 4 ) 4 ](H 2 O), (monoclinic, P 2 1 / c, a = 8.3354(9), b = 12.8304(13), c = 18.313(2) A, β = 90.025(2)°, V = 1958.5(4) A 3 , Z = 4) has been solved by direct methods and refined to R 1 = 0.052 using X-ray diffraction data collected from a crystal twinned on (001). There are five symmetrically independent Mg 2+ cations that are each octahedrally coordinated by four O atoms and two H 2 O groups. One symmetrically independent Ba 2+ cation is coordinated by eight O atoms and two H 2 O groups. The Mgϕ 6 octahedra (ϕ = O, H 2 O) and PO 4 tetrahedra form sheets parallel to (001). Their main elements are zigzag chains of the Mgϕ 6 edge-sharing octahedra. The chains are linked via common vertices to form an octahedral sheet in which Mg atoms are located at the vertices of the 6 3 hexagonal net. The PO 4 tetrahedra are above and below hexagonal rings of Mg octahedra and are linked to them by sharing common O vertices. The Ba atoms and H 2 O(1) and H 2 O(22) groups are located between the sheets providing their linkage into three-dimensional structure. The structure of rimkorolgite is closely related to that of bakhchisaraitsevite, Na 2 Mg 5 (PO 4 ) 4 7H 2 O. Both structures are based on the octahedral-tetrahedral sheets of the same type. In bakhchisaraitsevite, the sheets are linked into three-dimensional framework by edge-sharing between the Mgϕ 6 octahedra from two adjacent sheets, whereas in rimkorolgite, there is no linkage between adjacent sheets. The structure of rimkorolgite can be considered as bakhchisaraitsevite-like framework interrupted by the presence of large Ba 2+ cations.