Elektroneutrale Pb4O4 -Heterokubaneinheiten in den Aluminatsodalithen Ln4[Al12O24](Pb4O4)2 (Ln = Nd, Sm) / Electrically Neutral Pb4O4 Heterocubane Units in Aluminate Sodalites Ln4[Al12O24](Pb4O4)2 (Ln = Nd, Sm)

1997 ◽  
Vol 52 (4) ◽  
pp. 449-452 ◽  
Author(s):  
J.-P. Werner ◽  
Hk. Müller-Buschbaum

Abstract Single crystals of Ln4[Al12O24](Pb4O4)2 (Ln = Nd, Sm) have been prepared by flux techniques. The compounds crystallize with cubic symmetry, space group Oh-Pn3̄m, aNd = 9.514(1), aSm = 9.481(1) Å, Z = 1. The crystal structure is characterized by a [Al12O24]12- framework. Four of the eight six-membered rings of AlO4-tetrahedra per sodalite cage are centered by Ln3+ ions. The cages of the resulting electrically neutral network are filled with [Pb4O4]±0 heterocubane units. Oxygen of the heterocubane units completes the coordination spheres of the rare earth ions to hexagonal bipyramids.

1996 ◽  
Vol 51 (6) ◽  
pp. 883-887 ◽  
Author(s):  
J.-P. Werner ◽  
Hk. Müller-Buschbaum

Abstract Single Crystals of Pb2LnAl3O8 (Ln = Eu, Gd) have been prepared by flux techniques. The compounds crystallize with cubic symmetry, space group Oh-Pn3̅m, a(Eu) = 9.4578(5), a(Gd) = 9.4448(7) Å, Z = 4. The crystal structure is characterized by heterocubane units of the type Pb4O4 and hexagonal bipyramids of oxygen around the rare earth ions. These components form a network made of macro polyhedra of the type Pb4O4- LnO6- Pb4O4


1996 ◽  
Vol 51 (2) ◽  
pp. 240-244
Author(s):  
Hk. Müller-Buschbaum ◽  
St. Gallinat

Abstract Single crystals of (I) CuDyMo2O8 and (II) CuYbMo2O8 have been prepared by crystalli­sation from melts. Both com pounds crystallize with orthorhombic symmetry, space group D152h-Pbca with (I): a = 10.195(1), b = 9.721(2), c = 14.563(3); (II): a = 10.094(6), b = 9.628(9), c = 14.467(8) Å, Z = 8. The crystal structure is characterized by a triangular CuO3-polygon, a square antiprismatic coordination around the Rare Earth ions and the typical Mo O4 tetra­ hedra.


1995 ◽  
Vol 50 (2) ◽  
pp. 252-256 ◽  
Author(s):  
H. Szillat ◽  
Hk. Müller-Buschbaum

Single crystals of AgKCu3Mo4O16 have been prepared by crystallization from melts and investigated by X-ray diffractometer techniques. This compound crystallizes with monoclinic symmetry, space group C2h5 - P21/c, a = 5.056(1), b = 14.546(4), c = 19.858(9) Å, β = 86.64(5)°, Z = 4. The crystal structure of AgKCu3Mo4O16 is closely related to K2Cu3Mo4O16 showing ribbons of edge-sharing CuO6 and AgO7 polyhedra. The ribbons are linked by tetrahedrally coordinated molybdenum and K2O10 groups. Another kind of MoO4 tetrahedra occupies the cavities inside the ribbons. The crystal structure and the coordination of silver, copper, potassium and molybdenum by oxygen are discussed with respect to K2Cu3Mo4O16.


1995 ◽  
Vol 50 (4) ◽  
pp. 585-588 ◽  
Author(s):  
S. Frenzen ◽  
Hk. Müller-Buschbaum

Single crystals of Ba9Ru3.2Mn5.8O27 have been prepared by flux techniques. X-ray four circle diffractometer measurements led to trigonal (rhombohedral) symmetry, space group D53d - R3̄̄̄m , a = 5.7043(5), c = 21.255(4) Å , Z = 1. This phase is isotypic to BaRuO3. The crystal structure and the occupation of the M3O12 triple octahedra by ruthenium and manganese are discussed with respect to other oxides containing M3O12 groups in an ordered and disordered way.


1995 ◽  
Vol 50 (8) ◽  
pp. 1146-1150 ◽  
Author(s):  
Anne Utzolino ◽  
Karsten Bluhm

Single crystals of the compounds MnFe(BO3)O (I) and MnAl0.5Y0.5(BO3)O (II), were obtained by a B2O3 flux technique. I crystallizes with orthorhombic symmetry, space group D162h -Pnma (Nr.62), a = 939.92; b = 319.41; c = 939.11 pm; Z = 4 and II with monoclinic symmetry, space group C52h-P21/n (Nr. 14). a = 325.6; b = 955.1; c = 929.2 pm; β = 90.70° ; Z = 4. I is isotypic to the mineral Warwickite, while II is a distorded variant of this structure. All metal ions are octahedrally coordinated. Both structures contain isolated, trigonal planar BO3 units and oxygen atoms that are not coordinated to boron.


1994 ◽  
Vol 49 (3) ◽  
pp. 355-359 ◽  
Author(s):  
F.-D. Martin ◽  
H. Müller-Buschbaum

Abstract Single crystals of KBaCuV2O7Cl have been prepared by a flux technique and investigated by X-ray analysis. The compound crystallizes with tetragonal symmetry, space group C24v-P4 bm, a = 8.8581, c = 5.4711 Å, Z = 2. The crystal structure shows Cu2+ within a one sided strongly distorted CuO4Cl2 octahedron. The copper ion is shifted towards the nearer Cl- neighbour to form a CuO4Cl square pyramid. Two VO4 tetrahedra are connected to give stretched V2O7 double tetrahedra, and linked in planes via the oxygen corners of the CuO4Cl pyramids. The crystal structure and the structure of the complex BaO8Cl2 polyhedron are discussed.


1995 ◽  
Vol 50 (6) ◽  
pp. 879-883 ◽  
Author(s):  
H. Szillat ◽  
Hk. Müller-Buschbaum

Single crystals of Ag0.5Cu3V0,5Mo2,5O12 have been prepared by crystallization from melts and investigated by X -ray methods. They crystallize with triclinic symmetry, space group Ci1 -P 1̄ , a = 6.797(6), b = 8.575(6), c = 9.897(7) Å, α = 103.47(6), β = 103.69(6), γ = 101.48(6)° and Z = 4. The crystal structure is characterized by chains of edge-sharing CuO6 octahedra and CuO5 pyramids. Special features of this com pound are the square planar surrounding of Ag+ by O2− and a statistical distribution of molybdenum and vanadium at one point position.


1994 ◽  
Vol 49 (9) ◽  
pp. 1277-1281 ◽  
Author(s):  
Ch. Rabbow ◽  
Hk. Müller-Buschbaum

High temperature reactions of BaCO3/MnO/Er2O3 (3:1:1) led to single crystals of Ba3ErMn2O9. The product shows the structure of the hexagonal precious metal oxides Ba3LnRu2O9, but crystallizes with orthorhombic symmetry, space group C122v-Cmc21, a = 5.823 Å, b - 10.099 Å, c = 14.409 Å; Z = 4. The crystal structure is characterized by ErO6 octahedra, Mn2O9 face shared double octahedra and Ba2+ within cuboctahedral and anticuboctahedral coordination by O2-, respectively. In contrast to precious metal oxides the Mn-Mn distances inside the Mn2O9 double octahedra are elongated


1998 ◽  
Vol 53 (3) ◽  
pp. 287-290 ◽  
Author(s):  
B. Wedel ◽  
L. Wulff ◽  
Hk. Müller-Buschbaum

Abstract Single crystals of Pb2TeO5 have been prepared by flux techniques. X-ray investigations showed a new crystal structure with monoclinic symmetry, space group C4S -Cc, a = 13.099(3), b = 5.714(1), c = 7.520(2) Å, β = 123,80(3)°, Z = 4. Pb2TeO5 is characterized by 1∞[TeO5] chains of octahedra isolated from each other and incorporated into an edge, corner and face connected frame of PbO7 polyhedra. Possible positions of the lone pair of electrons of Pb2+ are estimated by calculations of Coulomb terms of lattice energy.


1996 ◽  
Vol 51 (3) ◽  
pp. 447-449 ◽  
Author(s):  
O. Sedello ◽  
Hk. Müller-Buschbaum

Abstract Single crystals of (Cu,Mn)3.66Mo3O12 have been prepared in sealed copper tubes. X-ray investiga­tions lead to orthorhombic symmetry, space group D2h16-Pnma, a = 5.1541(9), b = 10.788(2), c = 18.114(3)) Å , Z = 4. (Cu,Mn)3.66Mo3O12 is iso­typic to NaCo2.31Mo3O12 and (Cu,Co)3.75Mo3O12 with split positions for two of the metals.


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