Über Oxoplumbate(IV) Die Kristallstruktur von HT-Li2PbO3 [1] The Crystal Structure of HT-Li2PbO3 [1] / On Oxoplumbates(IV) The Crystal Structure of HT-Li2PbO3 [1]

1983 ◽  
Vol 38 (6) ◽  
pp. 661-664 ◽  
Author(s):  
Berthold Brazel ◽  
Rudolf Hoppe

Abstract Single crystals of HT-Li2PbO3 have been prepared by heating of mixtures of Rb2PbO3 and Li2O [Ag-cylinders, 600 °C, 100 d]. The structure determination [1005 symmetry independent l0(hkl), R = 5.85%, Rw = 5.35%, confirms space group C2/c with a = 548.60(16), b = 949.51(22), c = 1027.35(27) pm, β = 100.11(3)°, drö = 6.78 g · cm-3 , dpyk = 6.80 g · cm-3 , Z - 8. The NaCl-type structure variant is characterized by alter-nating layers of Li+ and Pb4+ /Li+ cations, which are all octahedrally coordinated. Effective Coordination Numbers, ECoN are calculated via Mean Fictive Ionic Radii, MEFIR.

1982 ◽  
Vol 37 (11) ◽  
pp. 1369-1374 ◽  
Author(s):  
Berthold Brazel ◽  
Rudolf Hoppe

For the first time single crystals of LT-Li2PbO3 have been prepared by decomposition of K2Li6[Pb2O8] [Incompletely closed Ag cylinders, sealed in Supremax-glass ampoule, vacuum, 690 °C, 100 d]. The structure determination [533Io(hkl); four-circle-diffractometer PW 1100, ω - scan, Mo - Kα, R = 4,86%, Rw = 4,93% confirms space group C2/c with a = 544.52(7), b = 926.12(7), c = 547,56(8) pm, β = 111.216(13)°, Z = 4, drö = 6.94 g · cm-3, dpyk = 6.89 g · cm-3. The NaCl-type structure variant is characterized by alternating layers of Li(2)+ and Li(l)+/Pb4+ cations. All atoms have octahedral coordination. The Madelung Part of Lattice Energy, MAPLE, Effective Coordination Numbers, ECoN, these via Mean Fictive Ionic Radii, MEFIR, are calculated.


1992 ◽  
Vol 45 (9) ◽  
pp. 1427 ◽  
Author(s):  
M Schlager ◽  
R Hoppe

Colourless single crystals of hitherto unknown CsNa2 [BO3] and RbNa2 [BO3] have been prepared by exchange reactions from intimate mixtures of Li3 [BO3], Na2O, CszO and Rb2O respectively. The new compounds are isostructural with KNa2 [BO3]. The structure determination from four-circle diffractometer data confirms the orthorhombic space group Pmmn with Z = 2. CsNa2 [BO3]: a = 626.33(4), b = 579.67(4), c = 560.09(5) pm (R = 2.0%, Rw = 1.8%). RbNa2 [BO3]: a = 613.3(2), b = 568.0(2), c = 554.9(2) pm (R = 6.0%, Rw = 4.0%). A characteristic feature of the structure is face-sharing of trigonal planar [BO3] groups with distorted anticuboctahedra of [MOI2]. The Madelung Part of the Lattice Energy (MAPLE), Effective Coordination Numbers ( ECoN ), Mean Fictive Ionic Radii (MEFIR) and Charge Distribution (CHARDI) are calculated and compared with results for KNa2 [BO3].


2015 ◽  
Vol 70 (3) ◽  
pp. 191-196 ◽  
Author(s):  
Olaf Reckeweg ◽  
Francis J. DiSalvo

AbstractThe new compounds LiK[C(CN)3]2 and Li[C(CN)3]·½ (H3C)2CO were synthesized and their crystal structures were determined. Li[C(CN)3]·½ (H3C)2CO crystallizes in the orthorhombic space group Ima2 (no. 46) with the cell parameters a=794.97(14), b=1165.1(2) and c=1485.4(3) pm, while LiK[C(CN)3]2 adopts the monoclinic space group P21/c (no. 14) with the cell parameters a=1265.7(2), b=1068.0(2) and c=778.36(12) pm and the angle β=95.775(7)°. Single crystals of K[C(CN)3] were also acquired, and the crystal structure was refined more precisely than before corroborating earlier results.


2017 ◽  
Vol 72 (11) ◽  
pp. 765-774
Author(s):  
Daniel Rudolph ◽  
Sonja Laufer ◽  
Ingo Hartenbach

AbstractAttempts to synthesize Pr4Mo7O27 using Pr, Pr6O11 and MoO3 in a molar ratio of 8:6:77 led to a main product of scheelite-type Pr0.667[MoO4] and few single crystals of the triclinic A-type Pr6Mo10O39. The latter crystallizes in space group P1̅ (a=945.25(1), b=1058.49(2), c=1815.16(3) pm; α=104.149(1), β=95.220(1), γ=102.617(1)°, Z=2). Its crystal structure comprises six crystallographically independent Pr3+ cations, eight tetrahedral [MoO4]2− units, and one [Mo2O7]2− entity. The cations display coordination numbers of seven (1×) and eight (5×), while the [MoO4]2− tetrahedra are surrounded by five Pr3+ cations each. The [Mo2O7]2− anions exhibit a coordination environment of seven Pr3+ cations. The attempt to synthesize PrF[MoO4] using PrOF (from in situ thermal decomposition of PrF[CO3]) as reagent did not lead to the desired product but to monoclinic B-type Pr6Mo10O39. This slightly less dense modification compared to its triclinic analogue crystallizes in space group C2/c (a=1247.93(3), b=1989.68(6), c=1392.52 (4) pm, β=100.505(2)°, Z=4) with three crystallographically independent Pr3+ cations, four [MoO4]2− tetrahedra, and again one [Mo2O7]2− unit in the crystal structure. Thus, both Pr6Mo10O39 modifications are better described with the structured formula Pr6[MoO4]8[Mo2O7]. The coordination numbers around the Pr3+ cations are seven (1×) and eight (2×) while all four [MoO4]2− anions are again surrounded by five Pr3+ cations each. Six of the latter represent the coordination environment around the [Mo2O7]2− entities. Besides the thorough comparison of the crystal structures single crystal Raman spectra were recorded for both Pr6Mo10O39 phases.


2020 ◽  
Vol 84 (5) ◽  
pp. 699-704
Author(s):  
Luca Bindi ◽  
Andrew C. Roberts ◽  
Cristian Biagioni

AbstractAlstonite, BaCa(CO3)2, is a mineral described almost two centuries ago. It is widespread in Nature and forms magnificent cm-sized crystals. Notwithstanding, its crystal structure was still unknown. Here, we report the crystal-structure determination of the mineral and discuss it in relationship to other polymorphs of BaCa(CO3)2. Alstonite is trigonal, space group P31m, with unit-cell parameters a = 17.4360(6), c = 6.1295(2) Å, V = 1613.80(9) Å3 and Z = 12. The crystal structure was solved and refined to R1 = 0.0727 on the basis of 4515 reflections with Fo > 4σ(Fo) and 195 refined parameters. Alstonite is formed by the alternation, along c, of Ba-dominant and Ca-dominant layers, separated by CO3 groups parallel to {0001}. The main take-home message is to show that not all structure determinations of minerals/compounds can be solved routinely. Some crystals, even large ones displaying excellent diffraction quality, can be twinned in complex ways, thus making their study a crystallographic challenge.


1996 ◽  
Vol 51 (11) ◽  
pp. 1583-1586 ◽  
Author(s):  
A. Mommertza ◽  
K. Dehnickea ◽  
J. Magull

Colourless single crystals of the title compound are obtained from a saturated solution of NaOSiPh3 in toluene in a humid atmosphere. We have characterized [Na4(OSiPh3)H2O)3] by IR spectroscopy and by a crystal structure determination. Space group R3, Z = 6 , R = 0.056. Lattice dimensions at -70°C: a = b = 1540.3 pm, c = 2639.6 pm. The compound has the structure of a Na4O4 heterocubane which is only slighty distorted and in which one of the sodium atoms is not hydrated and shows coordination number three.


1982 ◽  
Vol 37 (6) ◽  
pp. 688-694 ◽  
Author(s):  
Rolf M. Braun ◽  
Rudolf Hoppe

Abstract The new compound Rb2SnO2 was obtained as a light yellow powder by heating mixtures of the binary oxides (RbO0.48 + SnO, Rb: Sn = 2:1) under argon (sealed Ag cylinders, 600 °C, 3d). Subsequent annealing (550 °C, 8d and 500 °C, 17 d) led to light yellow transparent single crystals. Rb2SnO2 is extremely sensitive to moisture and decomposes into black products. It crystallizes orthorhombicly in the space group P212121-D42, with a = 5.761, b = 7.493, c= 11.167 Å, Z = 4, drö = 4.43 and dpyk = 4.46 gcm-3 , R= 11.8 and Rw = 12.0%. Effective Coordination Numbers, ECoN, these via Mean Fictive Ionic Radii, MEFIR, and the Madelung Part of Lattice Energy, MAPLE, have been calculated. Isotypic K2SnO2 was obtained similarly as a brown powder, a = 5.579, b = 7.246, c = 16.744 Å.


1999 ◽  
Vol 54 (12) ◽  
pp. 1609-1610 ◽  
Author(s):  
M. Karl ◽  
G. Seybert ◽  
W. Massa ◽  
K. Dehnicke

Blue moisture sensitive single crystals of [YbCl2(THF)5]+[WOCl4(THF)]- were obtained as a by-product from the reaction of the ytterbium trisamide Yb[N(SiMe3)2]3 with tungsten hexachloride in THF solution. The crystals were suitable for an X-ray crystal structure determination. Space group P2/c, Z = 2, lattice dimensions at -80 °C: a = 1192.5(1), b = 1117.1(1), c = 1349.9(1) pm, ß = 104.115(7)°, R = 0.0424. The structure consists of cations [YbCl2(THF)5]+ in which the ytterbium atom is coordinated in a pentagonalbipyramidal way by the chlorine atoms in the axial positions and by the oxygen atoms of the THF molecules in equatorial positions. Counterions are the well-known [WOCl4(THF)]- ions.


1998 ◽  
Vol 53 (3) ◽  
pp. 378-380
Author(s):  
Mike R. Kopp ◽  
Bernhard Neumüller

Abstract Single crystals of [Mo(CO)3(NCMe)(S′Bu)]2 (1) and [{Mo(CO)3}2{Mo(CO)2}{S′Bu}4] (2) were obtained by the reaction of [Mo(CO)3(NCMe)3] with [(PhCH2)2GaS′Bu]2 in 1,4-dio-xane. The X-ray structure determination of 1 showed the presence of a Mo2S2 four-membe-red ring with a Mo-Mo bond length of 296,7(1) pm. Space group Pbca, Z = 4, lattice dimen­sions at -80°C: a = 1588,2(3), b = 905,8(1), c = 1676,0(1) pm, R1 = 0,0555.


1995 ◽  
Vol 50 (1) ◽  
pp. 66-70 ◽  
Author(s):  
Inge Pabst ◽  
Peter Sondergeld ◽  
Mirjam Czjzek ◽  
Hartmut Fuess

The title compound has been prepared in two different ways: First, by boiling single crystals of [(C2H5)4N]HgCl3 in a mixture of n-hexane/n-octane [4:1] at T = 350 K, and second, in a synthesis from stoichiometric quantities of the components. X-ray structure analysis gave the stoichiometry [(C2H5)4N]2Hg3Cl8, monoclinic, space group P21, a = 7.538(3), b = 19.909(6), c = 10.274(3) Å, β = 95.13(1)°, V = 1535.7(9) A3, Z = 2. The basic [Hg3Cl8]2--units form broken zig-zag chains along [100]. The Hg–Cl distances within the [Hg3Cl8]2- clusters range from 2.315(3) to 2.755(4) Å. This is a new coordination type for halomercurates.


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