scholarly journals Nová data k výzkumu tvrdýitu z Krušné hory u Berouna (Česká republika)

2020 ◽  
Vol 28 (2) ◽  
pp. 406-411
Author(s):  
Luboš Vrtiška ◽  
Radana Malíková

During the revision of beraunite like minerals from old localities represented by historical samples in the mineralogical collection of the National Museum in Prague, the second occurrence of tvrdýite was confirmed in the iron ores from abandoned iron deposit Krušná hora in the Central Bohemia (Czech Republic). Krušná hora is situated about 12 km NW of Beroun (30 km WSW of Prague) in an area of the Ordovician sedimentary rocks of the Teplá-Barrandian unit. Tvrdýite forms brown-green, yellow-green to light-green radial aggregates up to 3 mm in size. Tvrdýite is monoclinic, space group C2/c with following unit-cell parameters refined from the X-ray powder diffraction data: a 20.529(9), b 5.105(2), c 18.869(8) Å, β 92.8(4)° and V 1975.1(8) Å3; its empirical formula is (Na+0.13Fe2+0.86Mg2+0.01)Σ1.00(Al3+2.39Fe3+0.57)Σ2.96(Fe3+1.93Al3+0.03)Σ1.96[(PO4)3.99(VO4)0.01]Σ4.00(OH)4.61(OH2)4.00·2H2O. The mineral was found in association with smaller bluish radial aggregates of unidentified Fe-Al phosphate (probably Al-rich dufrénite or different generation of tvrdýite).

1991 ◽  
Vol 6 (4) ◽  
pp. 228-230
Author(s):  
Slaheddine Kamoun

AbstractWith the help of Boulle's metathesis reaction, we have succeeded in preparing the compound [NH3(CH2)2NH3]2·P207. We describe its chemical preparation and main crystallographic features. The bis(ethylenediammonium) diphosphate salt is monoclinic, space group C2/c, with Z = 4. Unit cell parameters and powder diffraction data for this salt are reported.


1994 ◽  
Vol 9 (2) ◽  
pp. 98-104
Author(s):  
Jaakko Leppä-aho ◽  
Jussi Valkonen

X-ray powder diffraction data are reported for a series of isomorphous compounds of [Ln2(CrO4)3(H2O)5]·2H2O, where Ln=La, Pr, Nd, Sm, or Eu. The compounds crystallize in monoclinic space group P21/c (No: 14) with Z=4. Refined unit cell parameters and indexed powder diffraction patterns are given.


2020 ◽  
Vol 28 (2) ◽  
pp. 359-363
Author(s):  
Luboš Vrtiška ◽  
Petr Pauliš ◽  
Jiří Čejka ◽  
Radana Malíková ◽  
Zdeněk Dolníček ◽  
...  

A very rare bismuth sulphate, riomarinaite, was found in an old abandoned shaft on a Sn-W deposit Cínovec near Teplice, Northern Bohemia. This is first occurrence of this generally very rare mineral in the Czech Republic. Riomarinaite forms grey and blue acicular and columnar crystals up to 30 μm in size in association with native bismuth and bismuthinite. Riomarinaite is monoclinic, space group P21/n, the unit-cell parameters refined from X-ray powder diffraction data are: a 6.0091(19), b 13.328(5), c 6.483(3) Å, β 112.91(5)˚ and V 478.3(3) Å3. Chemical analyses of riomarinaite correspond to the empirical formula (Bi1.10Ca0.02)Σ1.12[(SO4)0.92(MoO4)0.08]Σ1.00(OH)1.33·H2O on the basis of S + Mo = 1 apfu. Raman bands connected with vibrations of (OH)-, H2O, (SO4)2- groups, Bi-O bonds and lattice modes were observed in the Raman spectrum of riomarinaite.


1989 ◽  
Vol 4 (3) ◽  
pp. 165-167 ◽  
Author(s):  
A. Elfakir ◽  
J.P. Souron ◽  
M. Quartern

AbstractThree isotopic orthovanadates MTh2 (VO4)3 with M = K, Rb, Cs have been syndiesized by solid state reaction. Single crystals of K Th2 (VO4)3 and Rb Th2 (VO4)3 were obtained. These compounds are isotypic with the corresponding orthophosphates: monoclinic, space group C2/c, Z = 4. Unit-cell parameters for die diree compounds were determined. Powder diffraction data for each phase are reported.


2021 ◽  
pp. 1-6
Author(s):  
Mariana M. V. M. Souza ◽  
Alex Maza ◽  
Pablo V. Tuza

In the present work, LaNi0.5Ti0.45Co0.05O3, LaNi0.45Co0.05Ti0.5O3, and LaNi0.5Ti0.5O3 perovskites were synthesized by the modified Pechini method. These materials were characterized using X-ray fluorescence, scanning electron microscopy, and powder X-ray diffraction coupled to the Rietveld method. The crystal structure of these materials is orthorhombic, with space group Pbnm (No 62). The unit-cell parameters are a = 5.535(5) Å, b = 5.527(3) Å, c = 7.819(7) Å, V = 239.2(3) Å3, for the LaNi0.5Ti0.45Co0.05O3, a = 5.538(6) Å, b = 5.528(4) Å, c = 7.825(10) Å, V = 239.5(4) Å3, for the LaNi0.45Co0.05Ti0.5O3, and a = 5.540(2) Å, b = 5.5334(15) Å, c = 7.834(3) Å, V = 240.2(1) Å3, for the LaNi0.5Ti0.5O3.


2021 ◽  
pp. 1-3
Author(s):  
J. Maixner ◽  
J. Ryšavý

X-ray powder diffraction data, unit-cell parameters, and space group for tetrazene nitrate monohydrate, C2H9N11O4, are reported [a = 5.205(1) Å, b = 13.932(3) Å, c = 14.196(4) Å, β = 97.826(3)°, unit-cell volume V = 1019.8(4) Å3, Z = 4, and space group P21/c]. All measured lines were indexed and are consistent with the P21/c space group. No detectable impurities were observed.


2021 ◽  
Vol 29 (2) ◽  
pp. 275-280
Author(s):  
Pavel Škácha ◽  
Jiří Sejkora

The Pb-Sb mineralization with dominant stibnite and plagionite and associated semseyite and zinkenite was found in an archive material collected at the Antimonitová vein, Bohutín, Březové Hory ore district (Czech Republic). Plagionite forms subhedral aggregates up to 1 mm in size. The unit-cell parameters of plagionite for monoclinic space group C2/c refined from the X-ray powder data are: a 13.4890(17), b 11.8670(14), c 19.997(2) Å, β 107.199(8)° and V 3057.9(6) Å3. Its chemical composition (average of 26 analyses, based on 30 apfu) corresponds to the empirical formula Pb5.02Sb8.15S16.82. Associated zinkenite is forming subhedral crystals up to 1 mm in size. Its empirical formula can be expressed as (Cu0.25Ag0.02Fe0.01)Σ0.28Pb9.22Sb22.19S41.31 (average of 26 analyses, based on 73 apfu). Semseyite aggregates have the empirical formula (Pb8.72Fe0.14)8.86Sb8.42S20.73 (average of 11 analyses, based on 38 apfu).


2002 ◽  
Vol 17 (1) ◽  
pp. 41-43 ◽  
Author(s):  
Rashmi ◽  
U. Dhawan

ZnGa2Te4 was found to crystallize in a defect tetrahedral structure with possible space group I4(82) with Z=2. Complete X-ray powder diffraction data were obtained and the unit cell parameters a and c and X-ray density were calculated. These were a=0.5930(1) nm, c=1.1859(3) nm, and Dx=5.7×103 kg/m3.


2017 ◽  
Vol 32 (3) ◽  
pp. 203-205
Author(s):  
Xiang Lin ◽  
Wei Ling Zhuo ◽  
Qiao Hong Du ◽  
Xi Lin Peng ◽  
Hui Li

X-ray powder diffraction data, unit-cell parameters, and space group for ertapenem side chain, C20H19N3O7S, are reported [a = 4.907(6) Å, b = 18.686(3) Å, c = 22.071(1) Å, α = γ = 90°, β = 90.759(5)°, unit-cell volume V = 2023.82 Å3, Z = 4, ρcal = 1.462 g cm−3, and space group P21/c]. All measured lines were indexed and are consistent with the P21/c space group. No detectable impurity was observed.


2013 ◽  
Vol 28 (4) ◽  
pp. 296-298
Author(s):  
R. Pažout ◽  
J. Maixner ◽  
A.S. Jones ◽  
J. Merna

X-ray powder diffraction data, unit-cell parameters, and space group for a new bis(β-diiminato) Cu(II) complex, C44H54CuN4O4, are reported [a = 8.683(3) Å, b = 11.216(3) Å, c = 11.753(4) Å, α = 66.27(3), β = 84.61(3), γ = 78.85(3), unit-cell volume V = 1027.77 Å3, Z = 1, and space group P-1]. All measured lines were indexed and are consistent with the P-1 space group. No detectable impurity was observed.


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