scholarly journals Notiz zur Kristallchemie von LiBa2Cu3O6 / Note on the Crystal Chemistry of LiBa2Cu3O6

1995 ◽  
Vol 50 (4) ◽  
pp. 681-683 ◽  
Author(s):  
G. Tams ◽  
Hk. Müller-Buschbaum ◽  
Ch. Lang

Single crystals of LiBa2Cu3O6 have been prepared by recrystallization from melts in a stream of dry Argon as well as by spontaneous CO2- LASER heating. It crystallizes with orthorhom bic symmetry, space group D232h - Fmmm, a = 8,219(2), b = 11,520 (2), c = 14,284(3) Å, Z = 8. The crystal structure is isotypic to NaBa2Cu3O6.

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.


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.


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.


1996 ◽  
Vol 51 (1) ◽  
pp. 85-89 ◽  
Author(s):  
St. Gallinat ◽  
Hk. Müller-Buschbaum

Abstract Single crystals of (I) BaCu0,41Pr2Mo4O16 and (II) BaYb2Mo4O16 have been prepared by flux technique. Both compounds crystallize with monoclinic symmetry, space group C62h-C2/c with (I): a = 5.352(11), b = 12.888(2), c = 19.399(4) Å; β = 90.89(3)°; (II): a = 5.181(7), b = 12.467(3), c -19.350(3) Å , β -91.93(2)°, Z = 4. The crystal structure is characterized by 1∞[BaMO12]-chains along [010]. In the first case the M positions are occupied by copper by about 41%, in the second case these positions remain completely unoccupied. With respect to the crystal chemistry of the reference compound Ba(Cu0.22Mg0,78)Nd2Mo4O16 all substances of the composition BaLn2Mo4O16 should be written as Ba▪Ln2Mo4O16 indicating the holes in the 1∞[BaMO12]-chains by ▪.


1995 ◽  
Vol 50 (5) ◽  
pp. 703-706 ◽  
Author(s):  
S. Münchau ◽  
Hk. Müller-Buschbaum

Abstract Single crystals of AgCdVO4 have been prepared in closed silver tubes using V2O5 as a flux. The light-orange crystals show orthorhombic symmetry, space group D162h-Pnma, a = 9.786(2), b = 6.994(1), c = 5.439(1) Å, Z = 4. The hitherto unknown AgCdVO4 is related to the Olivine structure but isotypic to Ag2CrO4 and NaCd4(VO4)3 respectively. The differences in crystal chemistry between the Olivine type, NaCd4(VO4)3 and AgCdVO4 are discussed.


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.


1995 ◽  
Vol 50 (2) ◽  
pp. 243-246 ◽  
Author(s):  
F.-D. Martin ◽  
Hk. Miiller-Buschbaum

Single crystals of K3CaV5O15 have been prepared by crystallization from melts. The com pound shows a new structure type with orthorhombic symmetry, space group D2h21-Cmma, a = 25.953(5), b = 15.688(3), c = 7.804(4) Å, Z = 8. Typical features of K3CaV5O15 are isolated cyclic V4O12 and V6O18 groups of corner sharing VO4 tetrahedra.


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