孔道结构化合物(H3NCH2CH2NH3)3[(VO)4(PO4)2(HPO4)4]的钒氧化态与热稳定性关系研究

热处理脱除有机模板易导致VPO体系孔道结构化合物结构破坏,从而阻碍此类材料的实际应用。以孔道结构化合物(H3NCH2CH2NH3)3[(VO)4 (PO4 )2 (HPO4 )4 ](简称V2P3 en)为研究对象,利用热分析(DSC TG)、动态原位高温X 射线衍射(XRD)及多功能X 射线光电子能谱(XPS)等方法,研究了该化合物在不同气氛热处理过程中模板脱除及结构演化规律,重点探讨了钒氧化态的变化对结构稳定性的影响。结果表明,加热过程中随着有机模板的分解脱除,形成较强的还原环境,骨架中的部分钒被还原(V4+→V3+),使原有的配位环境([VⅣO5]三角双锥、[VⅣO6]畸变八面体)与钒的氧化态不符而导致结构重组。因此,钒氧化态的变化是影响热稳定性的重要因素之一。     

Sergeysmirnovite,MgZn2(PO4)2 · 4H2O,a New Mineral from the Kester Deposit (Sakha-Yakutia,Russia)

Doklady Earth Sciences - Sergeysmirnovite, MgZn2(PO4)2 · 4H2O, is a new mineral from the oxidation zone of the Kester mineral deposit, Sakha-Yakutia, Russia. This mineral forms...     

Kampelite,Ba3Mg1.5Sc4(PO4)6(OH)3·4H2O,a new very complex Ba-Sc phosphate mineral from the Kovdor phoscorite-carbonatite complex (Kola Peninsula,Russia)

Mineralogy and Petrology - Kampelite, Ba3Mg1.5Sc4(PO4)6(OH)3·4H2O, is a new Ba-Sc phosphate from the Kovdor phoscorite-carbonatite complex (Kola Peninsula, Russia). It is orthorhombic, Pnma,...     

Epifanovite,NaCaCu5(PO4)4[AsO2(OH)2] · 7H2O: a New Mineral from the Kester Deposit,Sakha (Yakutia) Republic,Russia

Geology of Ore Deposits - Epifanovite, NaCaCu5(PO4)4[AsO2(OH)2] · 7H2O, a new natural copper, sodium and calcium arsenate–phosphate, has been found in a quartz–phosphate pocket...     

Structure and Mössbauer spectroscopy of barbosalite Fe2+Fe3+ 2 (PO4)2(OH)2 between 80 K and 300 K

Natural barbosalite Fe²⁺Fe³⁺ ₂ (PO₄)₂(OH)₂ from Bull Moose Mine, South Dakota, U.S.A., having ideal composition, was investigated with single crystal X-ray diffraction techniques, Mössbauer spectroscopy and SQUID magnetometry to redetermine crystal structure, valence state of iron and evolution of ⁵⁷Fe Mössbauer parameter and to propose the magnetic structure at low temperatures. At 298?K the title compound is monoclinic, space group P2₁/n, a _o ?= 7.3294(16)?Å, b _o ?=?7.4921(17)?Å, c _o ?=?7.4148 (18)?Å, β?=?118.43(3)°, Z?=?2. No crystallographic phase transition was observed between 298?K and 110?K. Slight discontinuities in the temperature dependence of lattice parameters and bond angles in the range between 150?K and 180?K are ascribed to the magnetic phase transition of the title compound. At 298?K the Mössbauer spectrum of the barbosalite shows two paramagnetic components, typical for Fe²⁺ and Fe³⁺ in octahedral coordination; the area ratio Fe³⁺/Fe²⁺ is exactly two, corresponding to the ideal value. Both the Fe²⁺ and the Fe³⁺ sublattice order magnetically below 173?K and exhibit a fully developed magnetic pattern at 160?K. The electric field gradient at the Fe²⁺ site is distorted from axial symmetry with the direction of the magnetic field nearly perpendicular to V_zz, the main component of the electric field gradient. The temperature dependent magnetic susceptibility exhibits strong antiferromagnetic ordering within the corner-sharing Fe³⁺-chains parallel to [101], whereas ferromagnetic coupling is assumed within the face-sharing [1?1?0] and [?1?1?0] Fe³⁺-Fe²⁺-Fe³⁺ trimer, connecting the Fe³⁺-chains to each other.     

Structural investigation of the synthetic CaAn(PO4)2 (An = Th and Np) cheralite-like phosphates

The crystallographic structures of the synthetic cheralite, CaTh(PO₄)₂, and its homolog CaNp(PO₄)₂ have been investigated by X-ray diffraction at room temperature. Rietveld analyses showed that both compounds crystallize in the monoclinic system and are isostructural to monazite LnPO₄ (Ln = La to Gd). The space group is P2₁/n (I.T. = 14) with Z = 2. The refined lattice parameters of CaTh(PO₄)₂ are a = 6.7085(8) Å, b = 6.9160(6) Å, c = 6.4152(6) Å, and β = 103.71(1)° with best fit parameters R _wp = 4.87%, R _p = 3.69% and R _B = 3.99%. For CaNp(PO₄)₂, we obtained a = 6.6509(5) Å, b = 6.8390(3) Å, c = 6.3537(8) Å, and β = 104.12(6)° and R _wp = 6.74%, R _p = 5.23%, and R _B = 6.05%. The results indicate significant distortions of bond length and angles of the PO₄ tetrahedra in CaTh(PO₄)₂ and to a lesser extent in CaNp(PO₄)₂. The structural distortions were confirmed by Raman spectroscopy of CaTh(PO₄)₂. A comparison with the isostructural compounds LnPO₄ (Ln = Ce and Sm) confirmed that the substitution of the large rare earth trivalent cations with Ca²⁺ and Th⁴⁺ introduces a distortion of the PO₄ tetrahedra.     

Orschallite,Ca3(SO3)2 · SO4 · 12H2O,a new calcium-sulfite-sulfate-hydrate mineral

Summary The new mineral orschallite, Ca₃(SO₃)₂SO₄ · 12H₂O, was found at the Hannebacher Ley near Hannebach, Eifel, Germany. Crystal structure analysis of the mineral, chemical analysis and water determination on synthetic material gave the composition Ca₃(SO₃)₂SO₄ · 12H₂O. The mineral crystallizes in space group with a = 11.350(1), c = 28.321(2) Å, V = 3159.7 ų, Z = 6, D_c = 1.87 Mg/m³, D_m = 1.90(3) Mg/m³. It is uniaxial positive with the optical constants = 1.4941, = 1.4960(4). The strongest lines in the powder pattern are (d-value (Å), I, hkl) 5.73, 100, 1 0 4/8.11, 80, 0 1 2/2.69, 80, 3 0 6/3.63, 60, 1 1 6/3.28, 40, 3 0 0. Refinement of the crystal structure led to a weighted residual of R_w = 0.043 for 600 observed reflections with I > 2(I) and 52 variable parameters.

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Orschallit, Ca₃(SO₃)₂SO₄ · 12H₂O, ein neues Kalzium-Sulfat-Sulfat-Hydrat-Mineral

Zusammenfassung Das neue Mineral Orschallit, Ca₃(SO₃)₂SO₄ · 12H₂O, wurde in der Hannebacher Ley bei Hannebach, Eifel, Deutschland gefunden. Eine Analyse der Kristallstruktur an einem Einkristall des natürlichen Materials, chemische Analyse und Wasserbestimmung an synthetischem Material ergaben die Zusammensetzung Ca₃(SO₃)₂SO₄ · 12H₂O. Das Mineral kristallisiert in der Raumgruppe mit a = 11.350(1), c = 28.321(2) Å, V = 3159.7 ų, Z = 6, D_c = 1.87 Mg/m³, D_m = 1.90(3) Mg/m³. Es ist optisch einachsig mit den optischen Konstanten = 1.4941, = 1.4960(4). Die stärksten Linien des Pulver-diagramms liegen bei (d-Wert (Å), I, hkl) 5.73, 100, 1 0 4/8.11, 80, 0 1 2/2.69, 80, 3 0 6/3.63, 60; 1 1 6/3.28, 40, 3 0 0. Die Verfeinerung der Kristallstruktur ergab einen gewichteten Residualwert R_w = 0.043 für 600 beobachtete Reflexe mit I > 2(I) und 52 variable Parameter.

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Mössbauer effect study of anapaite, Ca2Fe2+(PO4)2 · 4H2O, and of its oxidation products

Mössbauer spectra (MS) of anapaite (Ca₂ Fe²⁺(PO₄)₂?·?4H₂O) and of a sample after being immersed in a 4% H₂O₂ solution at room temperature (RT) over 12 days (hereafter an4ox) were collected at temperatures in the range 4.2 to 420?K and 11 to 300?K respectively. All MS consist of symmetrical doublets, hence magnetic ordering was not observed. The temperature dependencies of the Fe²⁺ centre shifts of anapaite and an4ox were analysed with the Debye model for the lattice vibrations. The characteristic Mössbauer temperatures were found as 370?K?±?25?K and 340?K?±?25?K, and the intrinsic isomer shifts as 1.427?±?0.005?mm/s and 1.418?±?0.005?mm/s respectively. From the external-field (60?kOe) MS recorded at 4.2 and 189?K for the non-treated sample, the principal component V _zz of the electric field gradient (EFG) is determined to be positive and the asymmetry parameter η?≈?0.2 and 0.4 respectively. The temperature variations of the quadrupole splittings, ΔE _Q(T), cannot be interpreted on the basis of the thermal population of the ⁵ D electronic levels resulting from the tetragonal compression of the O₆ co-ordination. The low-temperature linear behaviour of ΔE _Q(T) is attributed to a strong orbit-lattice coupling. A field of 60 kOe applied to anapaite at 4.2?K produces magnetic hyperfine splitting with effective hyperfine fields of ?136, ?254 and ?171?kOe along the principal axes Ox, Oy and Oz of the EFG tensor respectively. Additional oxidation treatments in solutions with various H₂O₂ concentrations up to 20% and subsequent Mössbauer experiments at room temperature, have revealed that the anapaite structure is not sensitive to oxidation since eventually only a small amount of Fe²⁺ (～6.5%) is converted into Fe³⁺.     

Thermodynamic properties of tooeleite,Fe63+(As3+O3)4(SO4)(OH)4·4H2O

Tooeleite, nominally Fe₆³⁺(As³⁺O₃)₄(SO₄)(OH)₄·4H₂O, is a relatively uncommon mineral of some acid-mine drainage systems. Yet, if it does occur, it does so in large quantities, indicating that some specific conditions favor the formation of this mineral in the system Fe-As-S-O-H. In this contribution, we report the thermodynamic properties of synthetic tooeleite. The sample was characterized by powder X-ray diffraction, scanning electron microscopy, extended X-ray absorption fine-structure spectroscopy, and Mössbauer spectroscopy. These methods confirmed that the sample is pure, devoid of amorphous impurities of iron oxides, and that the oxidation state of arsenic is 3+. Using acid-solution calorimetry, the enthalpy of formation of this mineral from the elements at the standard conditions was determined as −6196.6 ± 8.6 kJ mol⁻¹. The entropy of tooeleite, calculated from low-temperature heat capacity data measured by relaxation calorimetry, is 899.0 ± 10.8 J mol⁻¹ K⁻¹. The calculated standard Gibbs free energy of formation is −5396.3 ± 9.3 kJ mol⁻¹. The log K_sp value, calculated for the reaction Fe₆(AsO₃)₄(SO₄)(OH)₄·4H₂O + 16H⁺ = 6Fe³⁺ + 4H₃AsO₃ + SO₄²⁻ + 8H₂O, is −17.25 ± 1.80. Tooeleite has stability field only at very high activities of aqueous sulfate and arsenate. As such, it does not appear to be a good candidate for arsenic immobilization at polluted sites. An inspection of speciation diagrams shows that the predominance field of Fe³⁺ and As³⁺ overlap only at strongly basic conditions. The formation of tooeleite, therefore, requires strictly selective oxidation of Fe²⁺ to Fe³⁺ and, at the same time, firm conservation of the trivalent oxidation state of arsenic. Such conditions can be realized only by biological systems (microorganisms) which can selectively oxidize one redox-active element but leave the other ones untouched. Hence, tooeleite is the first example of an “obligatory” biomineral under the conditions prevailing at or near the Earth's surface because its formation under these conditions necessitates the action of microorganisms.     

Mineralogy, Mössbauer spectroscopy and electrical conductivity of heterosite (Fe3+, Mn3+)PO4

Mineralogical analysis, electrical conductivity and thermopower are reported for monocrystalline heterosite (Fe³⁺, Mn³⁺)PO₄ with the orthorhombic olivine-type structure. The ⁵⁷Fe Mössbauer spectrum could be adequately described using two Fe³⁺ doublets. By impedance spectroscopy (20 Hz–1 MHz) the electrical DC conductivity σ_DC and AC conductivity σ_AC were determined parallel (∥) and perpendicular to the [001] direction (space group Pnma) in the range ～160–440 K. The graph log σ_DC?1/T shows a slightly bent curve in both directions with activation energies of E _A ～0.30 and ～0.15 eV in the high and low temperature ranges, respectively. The reduced E _A is associated with electronic conduction; σ_DC ∥ [001] follows Mott’s T ^1/4 variable range hopping law at lower temperatures with hopping between localized levels. The values of σ_AC are increased relative to σ_DC at high frequencies and low temperatures, obeying Jonscher’s universal dynamic response law; for σ_AC ∥ [001], the variation with temperature of the frequency exponent is in fair agreement with the model of small polaron hopping. The absolute thermopower Θ is negative and low between ～295 and ～440 K, Θ does hardly vary with temperatures in both directions; the temperature independency of Θ ∥ [001] is consistent with the small polaron hopping model.     

(2)PALEOBOTANY (3)PALEOZOOLOGY

971349 Che;19 Jie(China Universityseienees,Beijing)The MammaljanShowjng ClimatieF盆uetuat应on—ExamPle of the Early Pleistoceneof Ge。FaunaS AS anMam-malian Faunas from Zhoukoudian,Beijing,China(ESI矛,ISSN 1 005一2321,CN 11一3370/P,4(2),1997,p·275一279,1 graph,1 table,10 ref) By analyses of the four local marnmalianfaunas from Zhoukoudian,Beijing,the EarlyPleistoeene elimatie and eeologieal environ-CN 11一1 905/Q1 53,1 graph,1735(2).1997,P.145一mental ehangespaper.One of1 .90M…     

Niedermayrite, Cu4Cd(SO4)2(OH)6 · 4H2O, a new mineral from the Lavrion Mining District, Greece

Summary Niedermayrite, Cu₄Cd(SO₄)₂(OH)₆ · 4H₂O, is a new mineral discovered in 1995 in the Km3-area of the Lavrion mining district, Greece. It forms tiny euhedral plates, commonly intergrown as green crusts up to several cm² in size on a matrix consisting of a brecciated marble with sphalerite, chalcopyrite, galena, greenockite, hawleyite and pyrite. Associated secondary minerals are gypsum, malachite, chalcanthite, brochantite, hemimorphite, hydrozincite, aurichalcite, one unknown Cd-sulfate, monteponite and otavite. Niedermayrite is non-fluorescent and has a bluish-green colour with vitreous lustre, the streak is white. The crystals are brittle with perfect cleavage parallel {010}. Optics: biaxial (–) with n(calc.), n, and n =1.609, 1.642(2), and 1.661(2), respectively; orientation n//b. The calculated density is 3.292 gcm^–3. The most prominent form is {010}. Analysis by electron microprobe gives CdO 16.5, CuO 45.7, SO₃ 21.6, H₂O 16.2 wt.% (calc. to 100% sum) and the empirical formula Cu_4.29Cd_0.96S_2.01O_11.28 · 6.71 H₂O (based on 18 oxygens p.f.u.). By TGA an H₂O content of 18.9 wt.% was obtained. The ideal formula (confirmed by the crystal structure refinement) is Cu₄Cd(SO₄)₂(OH)₆ · 4H₂O with a theoretical H₂O content of 17.2 wt.%. The strongest lines in the X-ray powder diffraction pattern (Gandolfi camera, visually estimated I, refined lattice parameters a = 5.535(2), b = 21.947(9), c = 6.085(2) Å, = 91.98(3)°) are: (d_obs[Å]/I_obs/hkl) (11.02/90/0 2 0), (5.874/20/0 1 1), (5.496/100/0 4 0), (5.322/25/0 2 1), (4.079/50/0 4 1), (3.660/20/0 6 0), (3. 437/30/1 5 0), (3.243/40/1 4 1), (2.470/30/2 4 0), (2.425/20/1 4 –2), (2.205/20/2 6 0) and (1.897/20/1 8 2). The mineral is monoclinic, P2₁/m, Z = 2, a = 5.543(1) Å, b = 21.995(4) Å, c = 6.079(1) Å, = 92.04(3)°, V = 740.7(2) ų. The crystal structure was determined by single crystal X-ray methods and was refined to R1= 0.026, wR2 = 0.056. The structure of niedermayrite is characterized by ² [Cu₄(OH)₆O₂]^2– sheets of edgesharing Cu coordination octahedra parallel to (010) with attached SO₄ tetrahedra, and intercalated CdO₂(H₂O)₄ octahedra with a system of hydrogen bonds. Close relationships to the crystal structures of christelite and campigliaite exist. The new mineral is named for Dr. Gerhard Niedermayr, Naturhistorisches Museum Wien, Austria.

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Niedermayrit, Cu₄Cd(SO₄)₂(OH)₆ · 4H₂O, ein neues Mineral aus dem Bergbaugebiet Lavrion, Griechenland

Zusammenfassung Niedermayrit, Cu₄Cd(SO₄)₂(OH)₆ · 4H₂O, ist ein neues Mineral, das 1995 im Km3-Bereich des Bergbaugebietes Lavrion, Griechenland, gefunden wurde. Es bildet winzige gut ausgebildete Plättchen, häufig miteinander verwachsen in grünen Krusten bis zu mehreren cm² Größe. Die Matrix besteht aus brecciösem Marmor mit Sphalerit, Chalcopyrit, Galenit, Greenockit, Hawleyit und Pyrit. Sekundäre Begleitminerale sind Gips, Malachit, Chalcanthit, Brochantit, Hemimorphit, Hydrozincit, Aurichalcit, ein unbekanntes Cd-Sulfat, Monteponit und Otavit. Niedermayrit fluoresziert nicht, besitzt blaugrüne Farbe mit Glasglanz, der Strich ist weiß. Die Kristalle sind spröd mit perfekter Spaltbarkeit parallel {010}. Optik: biaxial (–) mit n(ber.), n, und n=1.609, 1.642(2), und 1.661(2); Orientierung n//b. Die berechnete Dichte beträgt 3.292 gcm^–3. Die auffallendste Flächenform ist {010}. Die chemische Analyse mittels Mikrosonde ergibt CdO 16.5, CuO 45.7, SO₃ 21.6, H₂O 16.2wt.% (ber. auf 100% Summe) und die empirische Formel Cu_4.29Cd_0.96S_2.01O_11.28 · 6.71 H₂O (basierend auf 18 Sauerstoffatomen pro Formeleinheit). Aus der TGA wurde ein H₂O Gehalt von 18.9 Gew.% erhalten. Die Idealformel (bestätigt durch die Kristallstrukturverfeinerung) ist Cu₄Cd(SO₄)₂(OH)₆ · 4H₂O bei einem theoretischen H₂O-Gehalt von 17.2 Gew.%. Die stärksten Linien im Pulverdiffraktogramm (Gandolfi Kamera, visuell geschätzte I, verfeinerte Gitterkonstanten a = 5.535(2), b = 21.947(9), c = 6.085(2) Å, = 91.98(3)°) sind: (d_obs[Å]/I_obs/hkl) (11.02/90/0 2 0), (5.874/20/0 1 1), (5.496/100/0 4 0), (5.322/25/0 2 1), (4.079/50/0 4 1), (3.660/20/0 6 0), (3.437/30/1 5 0), (3.243/40/1 4 1), (2.470/30/2 4 0), (2.425/20/1 4 –2), (2.205/20/2 6 0) und (1.897/20/1 8 2). Das Mineral ist monoklin, P2₁/m, Z = 2, a = 5.543(1) Å, b = 21.995(4) Å, c = 6.079(1) Å, = 92.04(3)°, V = 740.7(2) ų Die Kristallstruktur wurde mittels Einkristallröntgenmethoden bestimmt und zu R1 = 0.026, wR2 = 0.056 verfeinert. Die Struktur von Niedermayrit ist durch ² [Cu₄(OH)₆O₂]^2– Schichten von kantenverknüpften Cu-Koordinationsoktaedern parallel (010) gekennzeichnet mit damit verbundenen SO₄ Tetraedern und dazwischen befindlichen CdO₂(H₂O)₄ Oktaedem mit einem Wasserstoffbrückensystem. Es bestehen enge Beziehungen mit den Kristallstrukturen von Christelit und Campigliait. Das neue Mineral ist nach Dr. Gerhard Niedermayr, Naturhistorisches Museum Wien, Österreich, benannt.

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Britvinite, Pb15Mg9(Si10O28)(BO3)4(CO3)2(OH)12O2, a new mineral species from Långban, Sweden

Britvinite, a new mineral species, has been found in manganese ore at the Långban deposit, Bergslagen ore district, Filipstad, Värmland County, Sweden. Calcite, barytocalcite, brucite, cerussite, and hausmannite are associated minerals. Britvinite occurs as pale yellow to colorless transparent plates with a white streak up to 0.2 × 0.5 × 0.5 mm in size, which are flat parallel to {001}; the luster is adamantine. Thin lamellae are flexible, whereas thick ones are brittle; the Mohs hardness is 3. The cleavage is eminent parallel to {001}. The calculated density is 5.51 g/cm³. In the infrared spectrum of the new mineral, the bands of (OH)?, (CO₃)^2?, and (BO₃)^3? are recorded, whereas those corresponding to water molecules are absent. Britvinite is optically biaxial and negative, α = 1.896(2), β = 1.903(2), γ = 1.903(2), 2Vmeas = 20(10), Z≈c. Dispersion is strong, r<v. The chemical composition (electron microprobe; H₂O determined with the Alimarin method, CO₂, with selective sorption) is (wt %) 7.95 MgO, 71.92 PbO, 0.41 Al₂O₃, 12.77 SiO₂, 2.2 H₂O, 2.1 CO₂, 2.67 B₂O₃ (calculated on the basis of structural data); total 100.02. The empirical formula calculated on the basis of 59 anions (O + OH) (Z = 1) is as follows: Pb_14.75Mg_9.03Si_9.73Al_0.37O_30.76(BO₃)_3.51(CO₃)_2.18(OH)_11.7. The simplified formula (Z = 2) is Pb_{7 + x} Mg_4.5(Si₅O₁₄)(BO₃)₂(CO₃)(OH,O)₇ (x < 0.5). The crystal structure of britvinite has been studied on a single crystal at 173 K; R = 0.0547. The new mineral is triclinic, space group P $ \bar 1 Britvinite, a new mineral species, has been found in manganese ore at the L?ngban deposit, Bergslagen ore district, Filipstad, V?rmland County, Sweden. Calcite, barytocalcite, brucite, cerussite, and hausmannite are associated minerals. Britvinite occurs as pale yellow to colorless transparent plates with a white streak up to 0.2 × 0.5 × 0.5 mm in size, which are flat parallel to {001}; the luster is adamantine. Thin lamellae are flexible, whereas thick ones are brittle; the Mohs hardness is 3. The cleavage is eminent parallel to {001}. The calculated density is 5.51 g/cm³. In the infrared spectrum of the new mineral, the bands of (OH)−, (CO₃)²⁻, and (BO₃)³⁻ are recorded, whereas those corresponding to water molecules are absent. Britvinite is optically biaxial and negative, α = 1.896(2), β = 1.903(2), γ = 1.903(2), 2Vmeas = 20(10), Z≈c. Dispersion is strong, r<v. The chemical composition (electron microprobe; H₂O determined with the Alimarin method, CO₂, with selective sorption) is (wt %) 7.95 MgO, 71.92 PbO, 0.41 Al₂O₃, 12.77 SiO₂, 2.2 H₂O, 2.1 CO₂, 2.67 B₂O₃ (calculated on the basis of structural data); total 100.02. The empirical formula calculated on the basis of 59 anions (O + OH) (Z = 1) is as follows: Pb_14.75Mg_9.03Si_9.73Al_0.37O_30.76(BO₃)_3.51(CO₃)_2.18(OH)_11.7. The simplified formula (Z = 2) is Pb_{7 + x} Mg_4.5(Si₅O₁₄)(BO₃)₂(CO₃)(OH,O)₇ (x < 0.5). The crystal structure of britvinite has been studied on a single crystal at 173 K; R = 0.0547. The new mineral is triclinic, space group P ; the unit-cell dimensions are a = 9.3409(8), b = 9.3597(7), c = 18.8333(14) ?, α = 80.365(6)°, β = 75.816(6)°, γ = 59.870(5)°, V = 1378.74(19) ?³. The structure consists of alternating TOT stacks (containing octahedral brucite-like and discontinuous tetrahedral (Si₅O₁₄)_∞∞ layers) and multilayered [Pb_7.1(OH)_3.6(CO₃)(BO₃)_1.75(SiO₄)_0.25]_∞∞ blocks. The strongest reflections in the X-ray powder diffraction pattern [d, ? (I, %)(hkl)] are 18.1(100)(001), 3.39(30)(12, 14, 015), 3.02(90)(006, 130, 106, 20, 11), 2.698(70)(332, 134, 030, 1), 2.275(30)(008, 420, 424), 1.867(30)(446, 239, 2.1.10, 18), 1.766(40)(151, 31, 10, 453, 542, 512, 42), 1.519(40)(0.0.12). The mineral has been named in honor of Sergei Nikolaevich Britvin (b. 1965), a Russian mineralogist. The type material of britvinite is deposited in the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow. The registration number is 3458/1. Original Russian Text ? N.V. Chukanov, O.V. Yakubovich, I.V. Pekov, D.I. Belakovsky, W. Massa, 2007, published in Zapiski Rossiiskogo Mineralogicheskogo Obshchestva, 2007, Pt CXXXVI, No. 6, pp. 18–25. The new mineral britvinite and its name were accepted by the Commission on New Minerals and Mineral Names, Russian Mineralogical Society, June 7, 2006, and approved by the Commission on New Minerals and Mineral Names, International Mineralogical Association, October 17, 2006.     

离子色谱法测定水样中S~(2-)、SO_3~(2-)、SO_4~(2-)、S_2O_3~(2-)

该种方法利用离子色谱仪的电导检测器与电化学检测器串联 ,十几分钟即可连续完成水中S2 - 、SO2 - 3 、SO2 - 4、S2 O2 - 3 的测定 ,方法具有快速、高效、方便、灵敏、选择性好等特点。方法的检出限分别为 :S2 - 12 5 μg/L ;SO2 - 3 2 2 4 μg/L ;SO2 - 45 0 μg/L ;S2 O2 - 35 0 μg/L。相对标准偏差在 1 5 %～ 6 9%之间 ,能够满足水中S2 - 、SO2 - 3 、SO2 - 4、S2 O2 - 3四种阴离子分析测试的需要。     

(NH_4)_2SO_4浸取EDTA-Zn测定试样中RE_2O_3

稀土元素的分析主要采用有机试剂萃取。偶氮试剂做为显色剂的比色分析,分析手续繁琐,也不易得到满意的分析结果,本文在EDTA容量法的基础上,采用较为简便的(NH4)2SO4浸取EDTA-Zn滴定法直接测定新型稀土总量,大大简化了试样的分析过程和操作手续。     

Taipingite-(Ce), (Ce73+, Ca2)Σ9Mg(SiO4)3[SiO3(OH)]4F3, a new mineral from the Taipingzhen REE deposit,North Qinling Orogen,central China

A new cerite group mineral species, taipingite-(Ce), ideally (Ce₇³⁺, Ca₂)_Σ9Mg(SiO₄)₃[SiO₃(OH)]₄F₃, has been found in the Taipingzhen rare earth element (REE) deposit in the North Qinling Orogen (NQO), Central China. It forms subhedral grains (up to approximately 100 ​μm ​× ​200 ​μm) commonly intergrown with the REE mineral assemblages and is closely associated with allanite-(Ce), gatelite-(Ce), törnebohmite-(Ce), fluocerite-(Ce), fluocerite-(La), fluorite, bastnäsite-(Ce), parisite-(Ce) and calcite. Taipingite-(Ce) is light red to pinkish brown under a binocular microscope and pale brown to colorless in thin section, and it is translucent to transparent with a grayish-white streak and vitreous luster. This mineral is brittle with conchoidal fracture; has a Mohs hardness value of approximately 5½ and exhibits no cleavage twinning or parting. The calculated density is 4.900(5) g/cm³. Optically, taipingite-(Ce) is uniaxial (+), with ω ​= ​1.808(5), ε ​= ​1.812(7), c ​= ​ε, and a ​= ​b ​= ​ω. Furthermore, this mineral is insoluble in HCl, HNO₃ and H₂SO₄. Electron microprobe analysis demonstrated that the sample was relatively pure, yielding the empirical formula (with calculated H₂O): (Ce_4.02La_1.64Nd_1.49Pr_0.41Sm_0.10Gd_0.02Ho_0.02Tm_0.01Lu_0.02Y_0.03Ca_0.66Mg_0.05Th_0.01–0.51)_Σ9(Mg_0.75Fe_0.25³⁺)_Σ1(SiO₄)₃{[SiO₃(OH)]_3.98[PO₃(OH)]_0.02}_Σ4(F_1.81OH_1.17Cl_0.02)_Σ3. Taipingite-(Ce) is trigonal and exhibits space group symmetry R3c with unit cell parameters a ​= ​10.7246(3) Å, c ​= ​37.9528(14) Å, V ​= ​3780.39(20) ų and Z ​= ​6. The strongest eight lines in the X-ray diffraction pattern are [d in Å(I)(hkl)]: 4.518(50)(202), 3.455(95)(122), 3.297(85)(214), 3.098(35)(300), 2.941(100)(02,10), 2.683(65)(220), 1.945(40)(238) and 1.754(40)(30,18). The crystal structure has been refined to a R₁ factor of 0.025, calculated for the 2312 unique observed reflections (Fo ​≥ ​4σ). The mineral is named after its discovery locality and is characterized as the F-dominant analogue of cerite-(Ce).     

Lahnsteinite, Zn4(SO4)(OH)6 · 3H2O, a new mineral from the Friedrichssegen Mine, Germany

A new mineral, lahnsteinite, has been found in the dump of the Friedrichssegen Mine, Bad Ems district, Rhineland-Palatinate (Rheinland-Pfalz), Germany. Lahnsteinite, occurring as colorless tabular crystals in the cavities of goethite, is associated with pyromorphite, hydrozincite, quartz, and native copper. The Mohs’ hardness is 1.5; the cleavage is perfect parallel to (001). D _calc = 2.995 g/cm³, D _meas = 2.98(2) g/cm³. The IR spectrum is given. The new mineral is optically biaxial, negative, α = 1.568(2), β = 1.612(2), γ = 1.613(2), 2V _meas = 18(3)°, 2V _calc = 17°. The chemical composition (wt %, electron microprobe data; H₂O was determined by gas chromatography of ignition products) is as follows: 3.87 FeO, 1.68 CuO, 57.85 ZnO, 15.83 SO₃, 22.3 H₂O, total is 101.53. The empirical formula is (Zn_3.3Fe_0.27Cu_0.11)_Σ3.91(S_0.98O₄)(OH)₅ · 3H_2.10O. The crystal structure has been studied on a single crystal. Lahnsteinite is triclinic, space group P1, a = 8.3125(6), b = 14.545(1), c = 18.504(2) Å, α = 89.71(1), β = 90.05(1), γ = 90.13(1)°, V = 2237.2(3) ų, Z = 8. The strong reflections in the X-ray powder diffraction pattern [d, Å (I, %)] are: 9.30 (100), 4.175 (18), 3.476 (19), 3.290 (19), 2.723 (57), 2.624 (36), 2.503 (35), 1.574 (23). The mineral has been named after its type locality near the town of Lahnstein. The type specimen of lahnsteinite is deposited in the Fersman Mineralogical Museum of the Russian Academy of Sciences, Moscow, registration number 4252/1.     

Thermodynamic properties of copper carbonates — malachite Cu2(OH)2CO3 and azurite Cu3(OH)2(CO3)2

The thermodynamic properties of the copper carbonates malachite and azurite have been studied by adiabatic calorimetry, by heat-flux Calvet Calorimetry, by differential thermal analysis (DTA) and by thermogravimetrie (TGA) analysis. The heat capacities, C _p ⁰ of natural malachite and azurite have been measured between 3.8 and 300 K by low-temperature adiabatic calorimetry. The heat capacity of azurite exhibits anomalous behavior at low temperatures. At 298.15 K the molar heat capacities C _p ⁰ and the third law entropies S _298.15 ⁰ are 228.5±1.4 and 254.4±3.8 J mol^?1 K^?1 for azurite and 154.3±0.93 and 166.3±2.5 J mol^?1 K^?1 for malachite. Enthalpies of solution at 973 K in lead borate 2PbO·B₂O₃ have been measured for heat treated malachite and azurite. The enthalpies of decomposition are 105.1±5.8 for azurite and 66.1±5.0 kJ mol^? for malachite. The enthalpies of formation from oxides of azurite and malachite determined by oxide melt solution calorimetry, are ?84.7±7.4 and ?52.5±5.9 kJ mol^?1, respectively. On the basis of the thermodynamic data obtained, phase relations of azurite and malachite in the system Cu²⁺-H₂O-CO₂ at 25 and 75 °C have been studied.