Zur Kenntnis eines Barium-Lanthanoid-Oxomanganats(IV, V): Ba3ErMn2O9 / On a Barium Rare-Earth Oxomanganate(IV, V): Ba3ErMn2O9

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

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.


1997 ◽  
Vol 52 (9) ◽  
pp. 1067-1071 ◽  
Author(s):  
O. Sfreddo ◽  
Hk. Müller-Buschbaum

Abstract Single crystals of Ba17Dy16Zn8Pt4O57 (I), Ba17Ho16Zn8Pt4O57 (II), Ba17Er16Zn8Pt4O57 (III) and Ba17YZn8Pt4O57 (IV) have been prepared by high temperature reactions using platinum crucibles. X-ray investigations led to tetragonal symmetry, space group C54h - I4/m, (I) - (IV): a = 22.905(1), 22.840(1), 22.795(1), 22.848(1) Å and c = 5.728(1), 5.722(1), 5.700(1), 5.709(1) Å,Z = 2. The crystal structure is characterized by small square, medium-sized quadrangular and large rectangular tunnels, which are filled by oxygen, barium and zinc. The polyhedra network is discussed with respect to the network of compounds of the Ba13Dy8Zn4Pt4O37 type.


1996 ◽  
Vol 51 (10) ◽  
pp. 1407-1410 ◽  
Author(s):  
B. Wedel ◽  
Hk. Müller-Buschbaum

Single crystals of Ba2Nb2TeO10) have been prepared by solid state reactions in air. X-ray investigations led to orthorhombic symmetry, space group D152h-Pbca, a = 7.242(4), b = 12.433(3), c = 9.932(3) Å. Z = 4. Nb5+ and Te6+ show octahedral coordination by O2- . The crystal structure is characterized by planes of edge- and corner-sharing NbO6- and TeO6octahedra. It is shown that in spite of nearly identical lattice constants of Ba2Nb2TeO10 with compounds of the composition M0,5BaNbTe2O9 the so far unknown crystals of these substances may not be derived from the Ba2Nb2TeO10 type.


1997 ◽  
Vol 52 (8) ◽  
pp. 989-993 ◽  
Author(s):  
B Mertens ◽  
Hk Müller-Buschbaum

Single crystals of Ba2,5Cd11(VO4)9 have been prepared by solid state reactions. The new compound crystallizes with orthorhombic symmetry, space group D142h-Pbcn, a = 20.842(6), b = 13.471(3), c = 11.838(9) Å, Z = 4. The crystal structure is characterized and dominated by CdO6 octahedra and unusual square pyramids of O2- around Cd2+ forming a three-dimensional [Cd11O36] network. The interstices are occupied by V5+ and Ba2+ ions. This results in VO4 tetrahedra and irregular BaO10 polyhedra isolated from each other. Occupation of the barium positions is deficient in agreement with the valence state V5+ and calculations of the coulomb terms of lattice energy.


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.


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 (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.


1995 ◽  
Vol 50 (6) ◽  
pp. 875-878 ◽  
Author(s):  
H. Szillat ◽  
Hk. Müller-Buschbaum

Single crystals of Rb0.6K0.4CuMo3O10 have been prepared by crystallization from melts and investigated by X-ray diffractometer technique. They crystallize with orthorhombic symmetry, space group D2h16 -Pnma , a = 8.606(2), b = 7.595(3), c - 13.660(7) Å, Z = 4. The crystal structure of Rb0.6K0.4CuMo3O10 is characterized by the rare octahedral coordination of molybdenum and is related to (NH4)2Mo3O10 with respect to the one-dimensional 1∞[Mo3O10]- chains.


1995 ◽  
Vol 50 (5) ◽  
pp. 707-711 ◽  
Author(s):  
H. Szillat ◽  
Hk. Müller-Buschbaum

Abstract Single crystals of (Cu,Co)3,75Mo3O12 have been prepared by recrystallization from melts and investigated by X-ray diffractometer techniques. The compound crystallizes with orthorhombic symmetry, space group D162h-Pnma, a = 5.092(1), b = 10.624(3), c = 17.804(4) Å, Z = 4 and is isotypic to NaCo2.31Mo3O12. The crystal structure is discussed and it is shown, that the trigonal prismatically coordinated copper positions are occupied in a different manner. One of the alternate sites is beside the centre of the prisms, and the other one is shifted towards one of the faces of the rectangular prism. This detail may be interpreted by assigning the valance states CuI and CuII. The MO6 octahedra are occupied statistically by copper and cobalt.


1995 ◽  
Vol 50 (11) ◽  
pp. 1653-1657 ◽  
Author(s):  
Anne Utzolino ◽  
Karsten Bluhm

Single crystals of Co1.5Ti0.5(BO3)O (I) and Co1.5Zr0.5(BO3)O (II) were obtained by a B2O3 flux technique. Both compounds crystallize with orthorhombic symmetry, space group D162h-Pnma (Nr. 62), I a = 928.1; b = 311.1; c = 940.1 pm; Z = 4 and II a = 949.5; b = 323.42; c = 934.7 pm; Z = 4. The compounds are isotypic to the mineral warwickite. All metal ions are octahedrally coordinated by oxygen ions. The structure contains isolated, trigonal planar BO3 units and oxygen that is not coordinated to boron.


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