Zur Kristallchemie der Barium-Oxometallat-Tellurite: Ba2M6Te2O21 (M = Niob und Tantal) / On the Crystal Chemistry of the Barium Oxometallate-Tellurites Ba2M6Te2O21 (M = Niobium and Tantalum)

1996 ◽  
Vol 51 (10) ◽  
pp. 1411-1414 ◽  
Author(s):  
B. Wedel ◽  
Hk. Miiller-Buschbaum
Keyword(s):  
Solid State ◽  
Single Crystals ◽  
Crystal Structures ◽  
Lone Pair ◽  
Lattice Energy ◽  
Solid State Reactions ◽  
Monoclinic Symmetry ◽  
X Ray ◽  
Symmetry Space ◽  
Symmetry Space Group

Single crystals of Ba2Nb6Te2O21 (I) and Ba2Ta6Te2O21 (II) have been prepared by solid state reactions in air. X-ray investigations led to monoclinic symmetry, space group C32h -C2/m, (I): a = 16.699(3), b = 5.671(2), c = 9.611(2) Å, β = 96.92(2), (II): a = 16.655(8), b = 5.667(2), c = 9.576(4) Å, β = 96.64(7), Z = 2. Nb5+ or Ta5+ show octahedral and Te4+ a one sided triangular coordination by O2- . The position and distance of the lone pair on Te4+ have been estimated by calculations of the Coulomb terms of the lattice energy. The polyhedron around Ba2+ may be described by a triply capped BaO8 cube. The crystal structures are dominated by a 3∞ [Nb6O21]12- network with incorporated Ba2+ and Te4+ ions.

Isolierte 1∞[TeO5]-Oktaederketten im Bleitellurat Pb2TeO5 / Isolated 1∞[TeO5] Chains of Octahedra in the Lead Tellurate Pb2TeO5

1998 ◽  
Vol 53 (3) ◽  
pp. 287-290 ◽  
Author(s):  
B. Wedel ◽  
L. Wulff ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Crystal Structure ◽  
Single Crystals ◽  
Lone Pair ◽  
Lattice Energy ◽  
Monoclinic Symmetry ◽  
Space Group ◽  
X Ray ◽  
Symmetry Space ◽  
Symmetry Space Group

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.

Zwei monokline Kupfer-Oxovanadate des Magnesiums mit geordneter Metallverteilung: m-Mg2CuV2O8 und MgCu2V2O8. Ein Beitrag zur Dimorphie von Mg2CuV2O8 / Two Monoclinic Copper Oxovanadates of Magnesium Showing Ordered Metal Distribution: m-Mg2CuV2O8 and MgCu2V2O8. A Contribution on Dimorphism of Mg2CuV2O8

1996 ◽  
Vol 51 (6) ◽  
pp. 817-821 ◽  
Author(s):  
O. Schrandt ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Solid State ◽  
Low Temperature ◽  
Single Crystals ◽  
Lattice Energy ◽  
Solid State Reactions ◽  
Tetrahedral Coordination ◽  
Monoclinic Symmetry ◽  
Crystal Forms ◽  
Symmetry Space ◽  
Symmetry Space Group

Abstract Single crystals of ra-Mg2CuV2O8 (I) and MgCu2V2O8 (II) have been prepared by solid state reactions. The orange (I) and dark red (II) crystals show monoclinic symmetry, space group C52h -P21/c, (I): a = 6.167(3), b = 8.172(5), c = 6.400(8) Å, β = 116.22(3)°, Z = 2; (II): a = 6.453(1), b = 8.342(2), c = 11.517(2)Å,β 90.44(2), Z = 4. Both compounds show ordered metal distributions and vanadium in tetrahedral coordination by oxygen. (I) is characterized by elongated CuO6 octahedra and (II) by trigonal CuO5 bipyramids. m-Mg2CuV2O8 is the low temperature form of the formerly investigated orthorhombic o-Mg2CuV2O8. Calculations of the Coulomb parts of the lattice energy of the two crystal forms are discussed

Kantenverknüpfte VO6-0ktaeder und PO4-Tetraeder in BaCa(VO)(PO4)2 / Edge-Connected VO6 Octahedra and PO4 Tetrahedra in BaCa(VO)(PO4)2

1997 ◽  
Vol 52 (5) ◽  
pp. 549-552 ◽  
Author(s):  
S. Meyer ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Melting Point ◽  
Single Crystals ◽  
Solid State Reactions ◽  
Monoclinic Symmetry ◽  
X Ray ◽  
Vanadyl Group ◽  
Symmetry Space ◽  
Symmetry Space Group

Abstract Single crystals of the new compound BaCa(VO)(PO4)2 have been prepared by solid state reactions below the melting point of the reactants in evacuated quartz tubes. X-ray investigations led to monoclinic symmetry, space group C2h5 - P21/c, a = 7.300(1), b = 7.053(1), c = 14.460(1) Å, β = 101,43(1)°, Z = 4. The crystal structure is characterized by layers of corner-and edge-connected PO4 tetrahedra and VO1+5 octahedra. There is an unusually short O(1)-O(4) distance in a VO6 octahedron of 2.44 Å associated with the sharing of edges with PO4 tetrahedra. The short V-O distance of 1.61 Å indicates a vanadyl group.

Cd0,73Cu0,27V2O6: Eine Verbindung mit Branneritstruktur / Cd0 ,73Cu0,27V2O6: A Compound with Brannerite Structure

1994 ◽  
Vol 49 (7) ◽  
pp. 927-930 ◽  
Author(s):  
S. Münchau ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Single Crystals ◽  
Solid State Reactions ◽  
Monoclinic Symmetry ◽  
Space Group ◽  
X Ray ◽  
Jahn Teller ◽  
Symmetry Space ◽  
Symmetry Space Group

Abstract Single crystals of Cd0.73Cu0.27V2O6 were prepared by solid state reactions. X-ray investigations lead to monoclinic symmetry, space group C32h-C2/m , a = 9.339, b = 3.5604, c = 6.893 Å, β = 111.85°, Z = 2. It belongs to the Brannerite structure, showing a statistical distribution of Cd2+ and Cu2+ on one point position. The crystal structure of Brannerites is discussed with respect to the distorted O2- octahedra around V5+ and the influence of the Jahn-Teller active Cu2+ ion to the shortened M2+O6 octahedra.

scholarly journals Zur Kenntnis eines Barium-Oxoniobat-Tellurats: Ba2Nb2TeO10 / On a Barium-Oxoniobate-Tellurate: Ba2Nb2TeO10

1996 ◽  
Vol 51 (10) ◽  
pp. 1407-1410 ◽  
Author(s):  
B. Wedel ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Single Crystals ◽  
Solid State Reactions ◽  
Orthorhombic Symmetry ◽  
X Ray ◽  
Lattice Constants ◽  
Group D ◽  
Symmetry Space ◽  
Symmetry Space Group

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.

Über ein cadmiumreiches Orthovanadat Ba2,5Cd11(VO4)9 mit Cadmium in oktaedrischer und tetragonal pyramidaler Koordination / On a Cadmium Rich Orthovanadate Ba2,5Cd11(VO4)9 Showing Cadmium in Octahedral and Square Pyramidal Coordination

1997 ◽  
Vol 52 (8) ◽  
pp. 989-993 ◽  
Author(s):  
B Mertens ◽  
Hk Müller-Buschbaum
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Single Crystals ◽  
Three Dimensional ◽  
Lattice Energy ◽  
Solid State Reactions ◽  
Orthorhombic Symmetry ◽  
Group D ◽  
Symmetry Space ◽  
Symmetry Space Group

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.

Synthese und Struktureines Strontium-Vanadyl-Phosphats: Sr2(VO)(PO4)2 / Synthesis and Structure of a Strontium Vanadyl Phosphate: Sr2(VO)(PO4)2

1996 ◽  
Vol 51 (7) ◽  
pp. 929-933 ◽  
Author(s):  
C. Wadewitz ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Solid State ◽  
Solid State Reactions ◽  
Vanadyl Phosphate ◽  
Monoclinic Symmetry ◽  
X Ray ◽  
Vanadyl Group ◽  
Dark Green ◽  
Symmetry Space ◽  
Oxygen Distance ◽  
Symmetry Space Group

Dark green single crystals of Sr2(VO)P2O8 have been prepared by solid state reactions in closed quartz tubes. X-ray investigations led to monoclinic symmetry, space group C2h6-I2/a, a = 6.744(4), b = 15.866(4), c = 7.032(2) Å, β = 115.41(2), Z = 4. Sr2(VO)P2O8 is isotypic to Sr2(VO)V2O8 and shows V4+ in split positions. The split positions are in non-centric octahedral coordination forming a short vanadium to oxygen distance typical for the vanadyl group. The crystal chemistry of the monovanadyl orthophate Sr2(VO)P2O8 is discussed considering related divanadyl phosphates.

Ein Beitrag zur Kristallchemie von Verbindungen mit Johillerit-Struktur: KCo3Cu(As2,58V0,42)O12 / On the Crystal Chemistry of Compounds with Johillerite Structure: KCo3Cu(As2,58V0,42)O12

1994 ◽  
Vol 49 (11) ◽  
pp. 1463-1466 ◽  
Author(s):  
D. Frerichs ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Solid State ◽  
Melting Point ◽  
Single Crystals ◽  
Crystal Chemistry ◽  
Structure Type ◽  
Solid State Reactions ◽  
Tetrahedral Coordination ◽  
Monoclinic Symmetry ◽  
Symmetry Space ◽  
Symmetry Space Group

Single crystals of KCo3Cu(As2.58V0.42)O12 were prepared by solid state reactions below the melting point of the reaction mixture (K2CO3, CuO, COC2O4, V2O5 and 3 As2O5 · 5H2O). It crystallizes with monoclinic symmetry, space group C62h-C2/c, a = 12.207, b = 12.730, c = 6.811 Å, β = 113.69°, Z = 4. The structure type is characterized by isolated twisted-square CuO4-polygons, CoO6-octahedra and a special 4+4-coordination of the potassium ion. As5+ and V5+ are in tetrahedral coordination with a partly statistical distribution of these ions.

Kristallstrukturuntersuchung am Barium-Yanadyl-Vanadat: Ba2(VO)V2O8 / Crystal Structure Investigation of the Barium Vanadyl-Vanadate: Ba2(VO)V2O8

1996 ◽  
Vol 51 (4) ◽  
pp. 489-492 ◽  
Author(s):  
J. Feldmann ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Single Crystals ◽  
Structure Type ◽  
Solid State Reactions ◽  
Tetrahedral Coordination ◽  
Structure Investigation ◽  
Monoclinic Symmetry ◽  
Symmetry Space ◽  
Symmetry Space Group

Abstract Single crystals of Ba2(VO)V2O8 have been prepared by solid state reactions of Ba2V2O7, V2O3 and V2O5 in sealed silica tubes. This compound crystallizes with monoclinic symmetry, space group C22 -P21, a = 8.1174(9), b = 5.9699(9), c = 9.2903(9) Å , β = 113.94(1)°, Z = 2. V 5+ shows tetrahedral coordination. V 4+ inside 1∞ [V (3)O4] chains is characterized by a square pyramidal coordination with a short apical V-O distance of 1.6 Å typically for vanadyl groups. Ba2(VO)V2O8 represents a new structure type and is not isotypic to Sr2(VO)V2O8.

Ba4Mn2Ag2O(As04)4 , ein Barium-Mangan-Oxid-Arsenat mit nichtlinearen O-Ag-O-Hanteln / Ba4Mn2Ag2O(AsO4)4, a Barium Manganese Oxide-Arsenate Showing Nonlinear O-Ag-O Dumbbells

1998 ◽  
Vol 53 (5-6) ◽  
pp. 512-516 ◽  
Author(s):  
M. Staack ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Bond Angle ◽  
Magnetic Measurements ◽  
Solid State Reactions ◽  
Metallic Silver ◽  
Monoclinic Symmetry ◽  
X Ray ◽  
Symmetry Space ◽  
Symmetry Space Group

Abstract Single crystals of Ba4Mn2Ag2O(AsO4)4 have been prepared by solid state reactions using metallic silver as reactant. X-ray techniques led to monoclinic symmetry, space group D2h-P2,/m, a = 8.739(2), b = 5.912(1), c = 9.440(2) Å, β = 115.21(1)°, Z = 1. The crystal structure is characterized by O-Ag-O dumbbells, bond angle = 165,3°, containing one oxygen atom not associated with the arsenate groups. Considering these facts Ba4Mn2Ag2O(AsO4)4 may be seen as an oxide-arsenate or an oxoargentate(I)-arsenate. Assuming the oxidation state +II for manganese, as confirmed by magnetic measurements, the compound has an oxygen deficite which was accounted for by a split position model.

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