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The new mineral calcioveatchite, ideally SrCaB11O16(OH)5·H2O, is a Ca-Sr-ordered analogue of veatchite. It was found at the Nepskoe potassium salt deposit, Irkutsk Oblast, Siberia, Russia in halite-sylvite and sylvite-carnallite rocks, with boracite, hilgardite, kurgantaite, hydroboracite, volkovskite, veatchite, anhydrite, magnesite, and quartz. Calcioveatchite forms prismatic or tabular crystals up to 1 × 1.5 × 3 mm3 and crystal clusters up to 3 mm across. It is transparent and colourless with vitreous lustre. Calcioveatchite is brittle, cleavage is perfect on {010}, the Mohs' hardness is ca 2, Dmeas is 2.58(1), and Dcalc is 2.567 g cm−3. Calcioveatchite is optically biaxial (+), α = 1.543(2), β = 1.550(5), γ = 1.626(2), 2Vmeas = 30(10)°, and 2Vcalc = 35°. The average chemical composition (wt.%, electron microprobe, H2O calculated by stoichiometry) is: CaO 7.05, SrO 20.70, B2O3 61.96, H2O 10.22, and total 99.93. The empirical formula, calculated based on 22 O apfu = O16(OH)5(H2O) pfu, is Sr1.23Ca0.78B10.99O16(OH)5·H2O. Calcioveatchite is monoclinic, space group P21, a = 6.7030(3), b = 20.6438(9), c = 6.6056(3) Å, β = 119.153(7)°, V = 798.26(8) Å3, and Z = 2. Polytype: 1M. The strongest reflections of the powder XRD pattern [d,Å(I,%)(hkl)] are: 10.35(100)(020), 5.633(12)(110), 5.092(10)(120), 3.447(14)(060), 3.362(13)(101, 051), 3.309(38)(–102), 2.862(10)(012), and 2.585(19)(080). The crystal structure was solved based on single-crystal XRD data, R1 = 0.0420. Calcioveatchite (calcioveatchite-1M) is an isostructural analogue of veatchite-1M with the 11-fold cation polyhedron occupied mainly by Sr [Sr0.902(8)Ca0.098(8)] whereas the 10-fold polyhedron is Ca dominant [Ca0.686(7)Sr0.314(7)]. The chemical composition of veatchite from five localities in Russia (Nepskoe), Kazakhstan (Shoktybay and Chelkar in the North Caspian Region), and the USA (Tick Canyon and Billie Mine in California) was studied, and it is shown to exist in nature as a continuous, almost complete isomorphous series which extends from Ca-free veatchite, Sr2B11O16(OH)5·H2O, to calcioveatchite with the composition Sr1.14Ca0.87B10.99O16(OH)5·H2O. [ABSTRACT FROM AUTHOR]

Titanosilicates comprise a broad class of materials with promising technological applications. The typical obstacle that restricts their industrial applicability is the high manufacturing cost due to the use of specific organotitanium precursors. We herein report a new approach to the synthesis of titanosilicates using an inexpensive inorganic precursor, ammonium titanyl sulfate (ATS or STA), (NH4)2TiO(SO4)2∙H2O. The latter is an intermediate in the processing of titanium-bearing concentrates produced from apatite-nepheline ores. In this paper, the new synthetic approach is exemplified by the microwave-assisted synthesis of IONSIVE-911, one of the most effective Cs-ion scavengers. The method can be modified to synthesize various titanosilicate compounds. [ABSTRACT FROM AUTHOR]

Yakubovichite, CaNi2Fe3+(PO4)3, a new mineral containing up to 20 wt% NiO, represents a novel type of terrestrial phosphate mineralization featuring an extreme enrichment in Ni. The mineral was discovered in the Hatrurim Formation (Mottled Zone)—pyrometamorphic complex whose outcrops are exposed in Israel and Jordan in the area coincident with the Dead Sea Transform fault system. Nickel-rich minerals in these assemblages also include Ni phosphides: halamishite Ni5P4, negevite NiP2, transjordanite and orishchinite—two polymorphs of Ni2P, nazarovite Ni12P5, polekhovskyite MoNiP2; Ni-spinel trevorite NiFe2O4, bunsenite NiO, and nickeliferous members of the hematite-eskolaite series, Fe2O3-Cr2O3 containing up to 2 wt% NiO. Yakubovichite forms polycrystalline segregations up to 0.2 mm in size composed of equant crystal grains, in association with crocobelonite, hematite, other phosphates, and phosphides. It has a deep yellow to lemon-yellow color, is transparent to translucent with vitreous luster, and has no cleavage. Mohs hardness = 4. Yakubovichite is orthorhombic, Imma, unit-cell parameters of the holotype material: a = 10.3878(10), b = 13.0884(10), c = 6.4794(6) Å, V = 880.94(2) Å3, Z = 4. Chemical composition of holotype material (electron microprobe, wt%): Na2O 1.82, K2O 1.76, CaO 6.37, SrO 0.49, BaO 1.37, MgO 2.13, NiO 21.39, CuO 0.16, Fe2O3 18.80, Al2O3 1.06, V2O3 0.44, Cr2O3 0.15, P2O5 44.15, total 100.09. The empirical formula calculated on the basis of 12 O atoms per formula unit is (Ca0.55Na0.29K0.18Ba0.04Sr0.02)1.08(Ni1.39Mg0.26Fe30.24+ V30.03+ Cu0.01Cr0.01)Σ1.94 (Fe30.90+ Al0.10)Σ1P3.02O12. Dcalc = 3.657 g cm–3. The strongest lines of powder XRD pattern [d(Å)(I)(hkl)]: 5.82(44)(011), 5.51(73)(101), 5.21(32)(200), 4.214(34)(121), 2.772(97)(240), 2.748(100)(202), 2.599(38)(400). Yakubovichite is the first mineral that crystallizes in the α-CrPO4 structure type. It has a direct synthetic analog, CaNi2Fe3+(PO4)3. Since yakubovichite is the first natural Ni-phosphate of non-meteoritic origin, the possible sources of Ni in the reported mineral assemblages are discussed. Pyrometamorphic rocks of the Hatrurim Formation were formed at the expense of the sediments belonging to a Cretaceous-Paleogene (Cretaceous-Tertiary) boundary (~66 Ma age). This geological frame marks the event of mass extinction of biological species on Earth that was likely caused by the Chicxulub impact event. The anomalous enrichment of pyrometamorphic assemblages in Ni may be related to metamorphic assimilation of Ni-rich minerals accumulated in the Cretaceous-Paleogene layer, which was formed due to a Chicxulub collision. [ABSTRACT FROM AUTHOR]

Crocobelonite, CaFe23+(PO4)2O, is a new natural oxyphosphate discovered in the pyrometamorphic complexes of the Hatrurim Formation in Israel and Jordan. Crocobelonite-bearing assemblages contain a series of anhydrous Fe-Ni phosphates, hematite, diopside, anorthite, and phosphides—barringerite Fe2P, transjordanite Ni2P, murashkoite FeP, halamishite Ni5P4, and negevite NiP2. Crocobelonite forms submillimeter-sized aggregates of prismatic to acicular crystals of saffron-red to pinkish-red color. There are two polymorphic modifications of the mineral whose structures are interrelated by the unit-cell twinning. Crocobelonite-2O is orthorhombic, Pnma, a = 14.2757(1), b = 6.3832(1), c = 7.3169(1) Å, V 666.76(1) Å3, Z = 4. This polymorphic modification is isotypic with synthetic oxy-phosphates A V 2 3 + P O 4 2 O where A = Ca, Sr, Cd. The crystal structure has been refined to RB = 0.71% based on powder XRD data, using the Rietveld method and the input structural model obtained from the single-crystal study. Chemical composition (electron microprobe, wt%) is: CaO 16.03, MgO 0.56, Fe2O3 43.37, Al2O3 0.33, SiO2 0.32, P2O5 39.45, Total 100.06. The empirical formula based on O = 9 apfu is C a 1.02 F e 1.94 3 + M g 0.05 A l 0.02 2.01 P 1.98 S i 0.02 2.00 O 9.00 The strongest lines of powder XRD pattern [d(Å)(I)(hkl)] are: 6.54(16)(200), 5.12(26)(201), 3.549(100)(102), 3.200(50) (401), 2.912(19)(220), 2.869(40)(411), 2.662(21)(501). Crocobelonite- 1M is monoclinic, P21/m, a = 7.2447(2), b = 6.3832(1), c = 7.3993(2) Å, β = 106.401(2)°, V = 328.252(14) Å3, Z = 2. This polymorphic modification does not have direct structural analogs. Its crystal structure has been solved and refined based on the single-crystal data to R1 = 1.81%. Chemical composition is: CaO 15.56, MgO 0.16, NiO 0.78, Fe2O3 41.28, Al2O3 0.45, V2O3 0.42, Cr2O3 0.23, TiO2 0.79, P2O5 39.94, Total 99.61, corresponding to the empirical formula (O = 9 a p f u) C a 0.99 F e 1.85 3 + N i 0.04 T i 0.04 A l 0.03 V 0.02 3 + C r 0.01 M g 0.01 2.00 P 2.01 O 9.00 with Dcalc = 3.604 g/cm3. The strongest lines of powder XRD pattern [d(Å)(I)(hkl)] are 6.98(17)(100), 4.40(22)(101), 3.547(100)(201), 3.485(21)(200), 3.195(50)(020), 2.855(38)(102), 2.389(33)(122). Crocobelonite represents a novel type of phosphate mineral formed by oxidation of phosphide minerals at temperatures higher than 1000 °C and near-atmospheric pressure (pyrolytic oxidation). [ABSTRACT FROM AUTHOR]