首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 109 毫秒
1.
The crystal structure of a new compound [Mg(H2O)4(SeO4)]2(H2O) (monoclinic, P2 1/a, a = 7.2549(12), b = 20.059(5), c = 10.3934(17) Å, β = 101.989(13), V = 1479.5(5) Å3) has been solved by direct methods and refined to R 1 = 0.059 for 2577 observed reflections with |F hkl | ≥ 4σ|F hkl |. The structure consists of [Mg(H2O)4(SeO4)]0 chains formed by alternating corner-sharing Mg octahedrons and (SeO4)2? tetrahedrons. O atoms of Mg octahedrons that are shared with selenate tetrahedrons are in a trans orientation. The heteropoly-hedral octahedral-tetrahedral chains are parallel to the c axis and undulate within the (010) plane. The adjacent chains are linked by hydrogen bonds involving H2O molecules not bound with M2+ cations.  相似文献   

2.
The crystal structure of a new compound Zn(SeO4)(H2O)2 (orthorhombic, Pbca, a = 9.0411(13), b = 10.246(2), c = 10.3318(15) Å, V = 957.1(3) Å3) has been solved by direct methods and refined to R 1 = 0.033 on the basis of 1076 observed reflections with |F hkl | ≥ 4σ|F hkl |. The structure contains one independent Zn2+ cation coordinated by two water molecules and four oxygen atoms of selenate group. The only independent (SeO4)2? tetrahedral oxoanion is tetradentate, sharing its corners with four adjacent [Zn2+O2(H2O4)]2+ octahedrons. The structure can be described as consisting of heteropolyhedral sheets parallel to the (001) plane and linked together into a three-dimensional network. The compound belongs to the variscite structure type and is the first structurally characterized selenate of this group.  相似文献   

3.
A new potassium uranyl selenate compound K(UO2)(SeO4)(OH)(H2O) has been synthesized for the first time using the technique of evaporation from water solution. Its crystal structure has been solved by direct methods (monoclinic, P21/c,a = 8.0413(9) Å, b = 8.0362(9) Å, c = 11.6032(14) Å, β = 106.925(2)°, V = 717.34(14) Å3) and refined to R 1 = 0.0319 (wR 2 = 0.0824) for 1285 reflections with |F 0| > 4σ F . The structure consists of [(UO2(SeO4)(OH)(H2O)]? chains extending along axis b. In the chains, the uranyl pentagonal bipyramids are linked via bridged hydroxyl anions and tetrahedral oxoanions [SeO4]2?. Potassium ions are situated between these chains. No chains of that type have been observed in uranyl compounds earlier, but they had been detected in the structures of butlerite, parabutlerite, uklonskovite, fibroferrite, and a number of synthetic compounds.  相似文献   

4.
The crystal structure of the unstable mineral alumoklyuchevskite K3Cu3AlO2(SO4)4 [monoclinic, I2, a = 18.772(7), b = 4.967(2), c = 18.468(7) Å, β = 101.66(1)°, V = 1686(1) Å] was refined to R 1 = 0.131 for 2450 unique reflections with F ≥ 4σF hkl. The structure is based on oxocentered tetrahedrons (OAlCu 3 7+ ) linked into chains via edges. Each chain is surrounded by SO4 tetrahedrons forming a structural complex. Each complex is elongated along the b axis. This type of crystal structure was also found in other fumarole minerals of the Great Tolbachik Fissure Eruption (GTFE, Kamchatka Peninsula, Russia, 1975–1976), klyuchevskite, K3Cu3Fe3+O2(SO4)4; and piypite, K2Cu2O(SO4)2.  相似文献   

5.
Fine-granular (<0.1 mm) flattened colorless transparent crystals of ivsite form white aggregates. The empirical formula (Na2.793Cu0.056)2.849HS2.016O8 is close to the ideal Na3H(SO4)2. The structure was refined up to R = 0.040. Ivsite has a monoclinic symmetry, P21/c, a = 8.655(1) Å, b = 9.652(1) Å, c = 9.147(1) Å, β = 108.76(1)°, V = 723.61(1) Å3, Z = 4. Na atoms occur at six- and seven-fold sites (NaO6 and NaO7); S atoms, in isolated SO4 tetrahedrons; these polyhedrons form a three-dimensional framework. The diagnostic lines of powder diffraction patterns (d[Å]–I–hkl) are 4.010–53–12-1, 3.949–87–012, 3.768–100–210, 3.610–21–20-2, 3.022–22–031, 2.891–42–22-2, 2.764–49–31-1, and 2.732–70–13-1.  相似文献   

6.
The paper reports new findings of avdoninite from deposits of active fumaroles in the Second Scoria Cone at the Northern Breach of the Great Fissure Tolbachik Eruption, Tolbachik Volcano, Kamchatka Peninsula, Russia. The crystal structure of the mineral has been determined for the first time, which has allowed reliable determination of its space group and unit cell dimensions, refinement of its formula K2Cu5-Cl8(OH)4 · 2H2O, and correct indexing of its X-ray powder diffraction pattern. Avdoninite is monoclinic, space group P21/c, a = 11.592(2), b = 6.5509(11), c = 11.745(2) Å, β = 91.104(6)°, V = 891.8(3) Å3, Z = 2. The crystal structure of this mineral has been determined on a single crystal R 1 [F > 4σ (F)] = 0.063. It is based on sheets of copper–oxo-chloride complexes [Cu5Cl8(OH)4]2– parallel to (100). The K+ cation and H2O molecules are interlayers.  相似文献   

7.
The crystal structure (R = 0.0194) of arcanite β-K2SO4 was studied on a single crystal from exhalations of the Arsenatnaya fumarole, Tolbachik Volcano (Kamchatka, Russia). The mineral crystallizes at a temperature of ≥350–430°C and associates with langbeinite, aphthitalite, hematite, tenorite, johillerite, and others. Arcanite is orthorhombic, Pnma, a = 7.4763(2) Å, b = 5.77262(16) Å, c = 10.0630(3) Å, V = 434.30(2) Å3, Z = 4. Its structure contains isolated SO4 tetrahedra, whereas K cations center ten- and nine-fold polyhedra.  相似文献   

8.
The single-crystal of humboldtine [Fe2+(C2O4) · 2H2O] was first synthesized and the crystal structure has been refined. Single-crystal X-ray diffraction data were collected using an imaging-plate diffractometer system and graphite-monochromatized MoKα radiation. The crystal structure of humboldtine was refined to an agreement index (R1) of 3.22% calculated for 595 unique observed reflections. The mineral crystallizes in the monoclinic system, space group C2/c, with unit cell dimensions of a = 12.011 (11), b = 5.557 (5), c = 9.920 (9) Å, β = 128.53 (3)?, V = 518.0 (8) Å3, and Z = 4. In this crystal structure, the alternation of oxalate anions [(C2O4)2?] and Fe2+ ions forms one-dimensional chain structure parallel to [010]; water molecules (H2O)0 create hydrogen bonds to link the chains, where (H2O)0 is essentially part of the crystal structure. The water molecules with the two lone electron pairs (LEPs) on their oxygen atom are tied obliquely to the chains, because the one lone electron pair is considered to participate in the chemical bonds with Fe2+ ions. Humboldtine including hydrogen bonds is isotypic with lindbergite [Mn2+(C2O4) · 2H2O]. The donor–acceptor separations of the hydrogen bonds in humboldtine are slightly shorter than those in lindbergite, which suggests that the hydrogen bonds in the former are stronger than those in the latter. The infrared and Raman spectra of single-crystals of humboldtine and lindbergite confirmed the differences in hydrogen-bond geometry. In addition, Fe2+–O stretching band of humboldtine was split and broadened in the observed Raman spectrum, owing to the Jahn–Teller effect of Fe2+ ion. These interpretations were also discussed in terms of bond-valence theory.  相似文献   

9.
Crystals of lead oxychloride Pb13O10Cl6 have been synthesized on the basis of high-temperature solid-state reactions. The Pb13O10Cl6 structure was studied using X-ray single-crystal diffraction analysis. The compound is monoclinic, and the space group is C2/c; the unit-cell dimensions are a = 16.1699(14), b = 7.0086(6), c = 23.578(2) Å, β = 97.75°, and V = 2647.6(4) Å3. The structure has been solved by direct methods and refined to R 1 = 0.0505 for 2671 observed unique reflections. The structure is a 3D framework consisting of OPb4 tetrahedrons. Chlorine atoms are located in the framework channels. The structure contains seven symmetrically independent Pb atoms, which are coordinated by 2 to 4 O2? and 2 to 4 Cl? anions. The synthesized compound is compared with other natural and synthetic lead oxyhalides.  相似文献   

10.
The crystal chemistry and the elastic behavior under isothermal conditions up to 9 GPa of a natural, and extremely rare, 3T-phlogopite from Traversella (Valchiusella, Turin, Western Alps) [(K0.99Na0.05Ba0.01)(Mg2.60Al0.20Fe 0.21 2+ )[Si2.71Al1.29O10](OH)2, space group P3112, with a = 5.3167(4), c = 30.440(2) Å, and V = 745.16(9) ų] have been investigated by electron microprobe analysis in wavelength dispersion mode, single-crystal X-ray diffraction at 100 K, and in situ high-pressure synchrotron radiation powder diffraction (at room temperature) with a diamond anvil cell. The single-crystal refinement confirms the general structure features expected for trioctahedral micas, with the inter-layer site partially occupied by potassium and sodium, iron almost homogeneously distributed over the three independent octahedral sites, and the average bond distances of the two unique tetrahedra suggesting a disordered Si/Al-distribution (i.e., 〈T1-O〉 ~ 1.658 and 〈T2-O〉 ~ 1.656 Å). The location of the H-site confirms the orientation of the O–H vector nearly perpendicular to (0001). The refinement converged with R 1(F) = 0.0382, 846 unique reflections with F O > 4σ(F O) and 61 refined parameters, and not significant residuals in the final difference-Fourier map of the electron density (+0.77/?0.37 e ?/Å3). The high-pressure experiments showed no phase transition within the pressure range investigated. The P–V data were fitted with a Murnaghan (M-EoS) and a third-order Birch-Murnaghan equation of state (BM-EoS), yielding: (1) M-EoS, V 0 = 747.0(3) Å3, K T0 = 44.5(24) GPa, and K′ = 8.0(9); (2) BM-EoS, V 0 = 747.0(3) Å3, K T0 = 42.8(29) GPa, and K′ = 9.9(17). A comparison between the elastic behavior in response to pressure observed in 1M- and 3T-phlogopite is made.  相似文献   

11.
A new mineral romanorlovite has been found in the upper, moderately hot zones of two fumaroles, Glavnaya Tenoritovaya (Major Tenorite) and Arsenatnaya (Arsenate), located at the second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. It is associated with avdoninite in both fumaroles, and in Glavnaya Tenoritovaya, it is also associated with belloite, sylvite, carnallite, mitscherlichite, sanguite, chlorothionite, eriochalcite, chrysothallite, and mellizinkalite. Romanorlovite occurs as prismatic, equant, or tabular tetragonal crystals up to 0.1 mm in size, crystal clusters up to 0.5 mm, and crusts up to 2 × 2 mm in area. The mineral is transparent with vitreous luster. Its color varies from yellow-brown to dark brown, and tiny crystals are honey- or golden-yellow. Cleavage is not observed. Romanorlovite is brittle. The Mohs hardness is ca ~3. The calculated density varies from 2.72 to 2.79 g/cm3 depending on the content of admixed Pb. The mineral is optically uniaxial (–), ω = 1.727(3), ε = 1.694(2). The Raman spectrum has been reported. The chemical composition of the holotype sample (wt %; electron microprobe data, contents of О and H calculated by stoichiometry) is as follows: 21.52 K, 0.89 Pb, 28.79 Cu, 0.02 Zn, 44.74 Cl, 4.85 Ocalc, 0.41 Hcalc, total 101.22. Its empirical formula calculated based on Cl25 with (ОН)4(Н2О)2 is K10.90Pb0.09Cu8.97Zn0.01Cl25(OH)4 · 2H2O. The simplified formula is K11Cu9Cl25(OH)4 · 2H2O (Z = 4). Romanorlovite is tetragonal, space group[ I4/mmm. The unit cell parameters are (1) holotype: a = 17.5804(7), c = 15.9075(6) Å, V = 4916.5(3) Å3; (2) the sample enriched in Pb on which the crystal structure was refined: a = 17.5538(19), c = 15.8620(17) Å, V= 4887.7(9) Å3. The strongest reflections of the powder XRD pattern (d, Å–I[hkl]) are 12.48–56[110], 11.74–36[101], 8.80–100[200], 7.97–34[002], 6.71–40[112], 3.165–32[512], 2.933–80[215, 433], 2.607–38[514]. The mineral is named in honor of Roman Yu. Orlov (1929-2005), Russian mineralogist and physicist, who worked in the Department of Mineralogy, Moscow State University.  相似文献   

12.
Three isotypic crystals, SiO2 (α-cristobalite), ε-Zn(OH)2 (wülfingite), and Be(OH)2 (β-behoite), with topologically identical frameworks of corner-connected tetrahedra, undergo displacive compression-driven phase transitions at similar pressures (1.5–2.0 GPa), but each transition is characterized by a different mechanism resulting in different structural modifications. In this study, we report the crystal structure of the high-pressure γ-phase of beryllium hydroxide and compare it with the high-pressure structures of the other two minerals. In Be(OH)2, the transition from the ambient β-behoite phase with the orthorhombic space group P212121 and ambient unit cell parameters a = 4.5403(4) Å, b = 4.6253(5) Å, c = 7.0599(7) Å, to the high-pressure orthorhombic γ-polymorph with space group Fdd2 and unit cell parameters (at 5.3(1) GPa) a = 5.738(2) Å, b = 6.260(3) Å, c = 7.200(4) Å takes place between 1.7 and 3.6 GPa. This transition is essentially second order, is accompanied by a negligible volume discontinuity, and exhibits both displacive and reversible character. The mechanism of the phase transition results in a change to the hydrogen bond connectivities and rotation of the BeO4 tetrahedra.  相似文献   

13.
The crystal structure and chemical composition of a crystal of (Mg14?x Cr x )(Si5?x Cr x )O24 (x ≈ 0.30) anhydrous Phase B (Anh-B) synthesized in the model system MgCr2O4–Mg2SiO4 at 12 GPa and 1600 °C have been investigated. The compound was found to be orthorhombic, space group Pmcb, with lattice parameters a = 5.900(1), b = 14.218(2), c = 10.029(2) Å, V = 841.3(2) Å3 and Z = 2. The structure was refined to R 1 = 0.065 using 1492 independent reflections. Chromium was found to substitute for both Mg at the M3 site (with a mean bond distance of 2.145 Å) and Si at the octahedral Si1 site (mean bond distance: 1.856 Å), according to the reaction Mg2+ + Si4+ = 2Cr3+. Such substitutions cause a reduction in the volume of the M3 site and an increase in the volume of the Si-dominant octahedron with respect to the values typically observed for pure Anh-B and Fe2+-bearing Anh-B. Taking into account that Cr3+ is not expected to be Jahn–Teller active, it appears that both the Cr3+–for–Mg and Cr3+–for–Si substitutions in the Anh-B structure decrease the distortion of the octahedra. Electron microprobe analysis gave the Mg13.66(8)Si4.70(6)Cr0.62(4)O24 stoichiometry for the studied phase. The successful synthesis of this phase provides new information for the possible mineral assemblages occurring in the Earth’s deep upper mantle and shed new light on the so-called X discontinuity that has been observed at 275–345 km depth in several subcontinental and subduction zone environments.  相似文献   

14.
The crystal structure of a new compound, (H3O)[(UO2)(SeO4)(SeO2OH)] (monoclinic, P21/n, a = 8.6682(19), b = 10.6545(16), c = 9.846(2) Å, β = 97.881(17)°, V = 900.7(3) Å3), was solved by direct methods and refined to R 1 = 0.050. The structure contains two symmetrically different Se atoms. The Se1 site is coordinated by three O atoms as is characteristic of Se4+ cations. The Se2 site is coordinated by four O atoms and forms selenate anion SeO 4 2? . The structure is based on selenite-selenate sheets [(UO2)(SeO4)(SeO2OH)]? linked by the interlayer H3O? ions. The sheets are parallel to (101). The structure is compared to that of schmiederite, Pb2Cu2(SeO3)(SeO4)(OH)4.  相似文献   

15.
The crystal structure of Pb6Bi2S9 is investigated at pressures between 0 and 5.6 GPa with X-ray diffraction on single-crystals. The pressure is applied using diamond anvil cells. Heyrovskyite (Bbmm, a = 13.719(4) Å, b = 31.393(9) Å, c = 4.1319(10) Å, Z = 4) is the stable phase of Pb6Bi2S9 at ambient conditions and is built from distorted moduli of PbS-archetype structure with a low stereochemical activity of the Pb2+ and Bi3+ lone electron pairs. Heyrovskyite is stable until at least 3.9 GPa and a first-order phase transition occurs between 3.9 and 4.8 GPa. A single-crystal is retained after the reversible phase transition despite an anisotropic contraction of the unit cell and a volume decrease of 4.2%. The crystal structure of the high pressure phase, β-Pb6Bi2S9, is solved in Pna2 1 (a = 25.302(7) Å, b = 30.819(9) Å, c = 4.0640(13) Å, Z = 8) from synchrotron data at 5.06 GPa. This structure consists of two types of moduli with SnS/TlI-archetype structure in which the Pb and Bi lone pairs are strongly expressed. The mechanism of the phase transition is described in detail and the results are compared to the closely related phase transition in Pb3Bi2S6 (lillianite).  相似文献   

16.
A new mineral, yegorovite, has been identified in the late hydrothermal, low-temperature assemblage of the Palitra hyperalkaline pegmatite at Mt. Kedykverpakhk, Lovozero alkaline pluton, Kola Peninsula, Russia. The mineral is intimately associated with revdite and megacyclite, earlier natrosilite, microcline, and villiaumite. Yegorovite occurs as coarse, usually split prismatic (up to 0.05 × 0.15 × 1 mm) or lamellar (up to 0.05 × 0.7 × 0.8 mm) crystals. Polysynthetic twins and parallel intergrowths are typical. Mineral individuals are combined in bunches or chaotic groups (up to 2 mm); radial-lamellar clusters are less frequent. Yegorovite is colorless, transparent with vitreous luster. Cleavage is perfect parallel to (010) and (001). Fracture is splintery; crystals are readily split into acicular fragments. The Mohs hardness is ～2. Density is 1.90(2) g/cm3 (meas) and 1.92 g/cm3 (calc). Yegorovite is biaxial (?), with α = 1.474(2), β = 1.479(2), and γ = 1.482(2), 2V meas > 70°, 2V calc = 75°. The optical orientation is X ∧ a ～ 15°, Y = c, Z = b. The IR spectrum is given. The chemical composition determined using an electron microprobe (H2O determined from total deficiency) is (wt %): 23.28 Na2O, 45.45 SiO2, 31.27 H2Ocalc; the total is 100.00. The empirical formula is Na3.98Si4.01O8.02(OH)3.98 · 7.205H2O. The idealized formula is Na4[Si4O8(OH)4] · 7H2O. Yegorovite is monoclinic, space group P21/c. The unit-cell dimensions are a = 9.874, b= 12.398, c = 14.897 Å, β = 104.68°, V = 1764.3 Å3, Z = 4. The strongest reflections in the X-ray powder pattern (d, Å (I, %)([hkl]) are 7.21(70)[002], 6.21(72)[012, 020], 4.696(44)[022], 4.003(49)[211], 3.734(46)[\(\bar 2\) 13], 3.116(100)[024, 040], 2.463(38)[\(\bar 4\)02, \(\bar 2\)43]. The crystal structure was studied by single-crystal method, R hkl = 0.0745. Yegorovite is a representative of a new structural type. Its structure consists of single chains of Si tetrahedrons [Si4O8(OH)4]∞ and sixfold polyhedrons of two types: [NaO(OH)2(H2O)3] and [NaO(OH)(H2O)4] centered by Na. The mineral was named in memory of Yu. K. Yegorov-Tismenko (1938–2007), outstanding Russian crystallographer and crystallochemist. The type material of yegorovite has been deposited at the Fersman Mineralogical Museum of Russian Academy of Sciences, Moscow.  相似文献   

17.
We have collected high resolution neutron powder diffraction patterns from Na2SO4·10D2O over the temperature range 4.2–300 K following rapid quenching in liquid nitrogen, and over a series of slow warming and cooling cycles. The crystal is monoclinic, space-group P21/c (Z = 4) with a = 11.44214(4) Å, b = 10.34276(4) Å, c = 12.75486(6) Å, β = 107.847(1)°, and V = 1436.794(8) Å3 at 4.2 K (slowly cooled), and a = 11.51472(6) Å, b = 10.36495(6) Å, c = 12.84651(7) Å, β = 107.7543(1)°, V = 1460.20(1) Å3 at 300 K. Structures were refined to R P (Rietveld powder residual, \( R_{P} = {{\sum {\left| {I_{\text{obs}} - I_{\text{calc}} } \right|} } \mathord{\left/ {\vphantom {{\sum {\left| {I_{\text{obs}} - I_{\text{calc}} } \right|} } {\sum {I_{\text{obs}} } }}} \right. \kern-\nulldelimiterspace} {\sum {I_{\text{obs}} } }} \)) better than 2.5% at 4.2 K (quenched and slow cooled), 150 and 300 K. The sulfate disorder observed previously by Levy and Lisensky (Acta Cryst B34:3502–3510, 1978) was not present in our specimen, but we did observe changes with temperature in deuteron occupancies of the orientationally disordered water molecules coordinated to Na. The temperature dependence of the unit-cell volume from 4.2 to 300 K is well represented by a simple polynomial of the form V = ? 4.143(1) × 10?7 T 3 + 0.00047(2) T2 ? 0.027(2) T + 1437.0(1) Å3 (R 2 = 99.98%). The coefficient of volume thermal expansion, α V , is positive above 40 K, and displays a similar magnitude and temperature dependence to α V in deuterated epsomite and meridianiite. The relationship between the magnitude and orientation of the principal axes of the thermal expansion tensor and the main structural elements are discussed; freezing in of deuteron disorder in the quenched specimen affects the thermal expansion, manifested most obviously as a change in the behaviour of the unit-cell parameter β.  相似文献   

18.
Synthetic CaAlSiO4F, the Al-F analog of titanite, has been investigated using single-crystal synchrotron diffraction experiments at Beamline X06DA (Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland) and Raman spectroscopy. The presented structural model with 40 parameters was refined against 506 unique reflections to a final R o b s of 0.026 (space group A2/a, a = 6.9120(11), b = 8.5010(10), c = 6.435(2) Å, β = 114.670(11)°, and Z = 4) and exhibits less distorted coordination polyhedra than earlier models from powder data. Vibrational spectra were calculated in harmonic approximation at the Γ point from fully relaxed energy optimisations of the crystal structure, using 3D-periodic density functional theory with Gaussian basis sets and the software CRYSTAL06. The lattice parameters of the fully relaxed structure were in good agreement with the experimental values, with the calculated values 0.8 ± 0.4 % too large; the monoclinic angle was calculated 0.4° too large. The agreement of the calculated Raman frequencies with the observed ones was very good, with standard deviation ±3 cm?1 and maximum deviations of ±7 cm?1. Furthermore, a detailed discussion of the atomic displacements associated with each Raman mode is given.  相似文献   

19.
Avdoninite, a new mineral species, has been found together with euchlorite, paratacamite, atacamite, belloite, and langbeinite hosted in exhalation sediments of the Yadovitaya fumarole in the Second Cinder Cone at the Northern Breach of the Great Fissure Tolbachik Eruption, Tolbachik volcano, Kamchatka Peninsula, Russia. Avdoninite occurs as imperfect, short prismatic and thick tabular crystals up to 0.2 mm long, with (001) and (100) forms, crystal aggregates, and pseudomorphs (together with atacamite) after melanothallite observed. The new mineral is brittle, with the Mohs hardness 3 (for aggregates). Density is 3.03 g/cm3 (meas.) and 3.066 g/cm3 (calc.). Avdoninite is biaxial and optically neutral, with α = 1.669, β = 1.688, γ = 1.707, 2V = ?90°. Dispersion is not observed. Optical orientation: Y = c, X = b? Pleochroism is absent. The infrared spectrum suggests the presence of water molecules in avdoninite. Electron microprobe chemical analysis has given (wt %) K2O 11.94 (±0.4), CuO 51.43 (±0.7), Cl 37.07 (±0.6), H2O (determined by the Penfield method) 6.9, ?O=Cl2 ?8.37, total 98.97. The empirical formula is K1.96Cu5.00Cl8.09(OH)3.87. · 1.03H2O. Avdoninite is monoclinic, space group P2/m, P2, or Pm; a = 24.34(2) Å, b = 5.878(4) Å, c = 11.626(5) Å, β = 93.3(1)°, V = 1660.6(20) Å3, Z = 4. The compatibility index is good: 1 ? K p/K c = 0.056 for D calc and 0.044 for D meas. The strongest lines in the X-ray powder diffraction pattern (d, Å (I, %) (hkl)) are 11.63(100)(001), 5.88(20)(010), 5.80(27)(002), 5.73(17)(\(\overline 1 \)02), 2.518(19)(21\(\overline 4 \)), 2.321(17)(005). Avdoninite is identical to a technogenic analogue previously described from the Blyava volcanic-hosted massive sulfide deposit, Orenburg oblast, Russia. The new mineral is named after Vladimir Nikolaevich Avdonin (born 1925), a senior researcher of the Ural Geological Museum of the Ural State Mining University. The type material of avdoninite from Kamchatka is deposited in the Mineralogical Museum of the Department of Mineralogy, St. Petersburg State University, St. Petersburg, Russia. The registration number is 19175.  相似文献   

20.
Based on a study of samples found in the Khibiny (Mt. Rasvumchorr: the holotype) and Lovozero (Mts Alluaiv and Vavnbed) alkaline complexes on the Kola Peninsula, Russia, tinnunculite was approved by the IMA Commission on New Minerals, Nomenclature, and Classification as a valid mineral species (IMA no. 2015-02la) and, taking into account a revisory examination of the original material from burnt dumps of coal mines in the southern Urals, it was redefined as crystalline uric acid dihydrate (UAD), C5H4N4O3 · 2H2O. Tinnunculite is poultry manure mineralized in biogeochemical systems, which could be defined as “guano microdeposits.” The mineral occurs as prismatic or tabular crystals up to 0.01 × 0.1 × 0.2 mm in size and clusters of them, as well as crystalline or microglobular crusts. Tinnunculite is transparent or translucent, colorless, white, yellowish, reddish or pale lilac. Crystals show vitreous luster. The mineral is soft and brittle, with a distinct (010) cleavage. Dcalc = 1.68 g/cm3 (holotype). Tinnunculite is optically biaxial (–), α = 1.503(3), β = 1.712(3), γ = 1.74(1), 2Vobs = 40(10)°. The IR spectrum is given. The chemical composition of the holotype sample (electron microprobe data, content of H is calculated by UAD stoichiometry) is as follows, wt %: 37.5 О, 28.4 С, 27.0 N, 3.8 Hcalc, total 96.7. The empirical formula calculated on the basis of (C + N+ O) = 14 apfu is: C4.99H8N4.07O4.94. Tinnunculite is monoclinic, space group (by analogy with synthetic UAD) P21/c. The unit cell parameters of the holotype sample (single crystal XRD data) are a = 7.37(4), b = 6.326(16), c = 17.59(4) Å, β = 90(1)°, V = 820(5) Å3, Z = 4. The strongest reflections in the XRD pattern (d, Å–I[hkl]) are 8.82–84[002], 5.97–15[011], 5.63–24[102?, 102], 4.22–22[112], 3.24–27[114?,114], 3.18–100[210], 3.12–44[211?, 211], 2.576–14[024].  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号