Neue Einsichten zur Stabilisierung des Hulsit-Strukturtyps am Beispiel von MnII,2MnIII(BO3)O2 und MnIISrMnIII(BO3)O3 / New Insights into the Stabilization of the Hulsite Structure During Crystal Structure Determination of MnII2MnIII(BO3)O2 and MnIISrMnIII(BO3)O2

1996 ◽  
Vol 51 (10) ◽  
pp. 1433-1438 ◽  
Author(s):  
Anne Utzolino ◽  
Karsten Bluhm

The compounds MnII2MnIII(BO3)O2 (I) and MnIISrMnIII(BO3)O2 (II) were prepared by using a B2O3 flux technique. Single crystals were investigated by X-ray diffraction. I showed orthorhombic symmetry, space group D92h - Pbam (No. 55), a = 926.0; b = 1241.5; c = 304.96pm ; Z = 4 and II monoclinic symmetry, space group C12h - P2/m (No. 10), a = 1107.5; b = 311.04; c = 542.93 pm, β = 95,10(2)°; Z = 2. MnII2MnIII(BO3)O2 i is isotypic with the mineral Ludwigite while MnnIISrMnmIII(BO3)O2 is isostructural with the mineral Hulsite. In the structure of MnII2Mnlll(BO3)O2 (I) all metal point positions showed octahedral oxygen coordination, one point position is occupied by Mn3+ . The structure of Mnll2Sr2Mnlll2(BO3)2O4 (II) contains five octahedrally coordinated metal sites, three of them statistically occupied by Mn2+ or Mn 3+ and Sr2+. The incorperation of Sr2+ seems to be responsible for the Hulsite structure. Both structures contain isolated, trigonal planar BO3 units and oxygen atoms that are not coordinated to boron.

1996 ◽  
Vol 51 (3) ◽  
pp. 305-308 ◽  
Author(s):  
Anne Utzolino ◽  
Karsten Bluhm

Abstract The compounds Co5Sn(BO3)2O4 (I) and Co5Mn(BO3)2O4 (II) were prepared by using a B2O3 flux technique. Single crystals were investigated by X-ray diffraction and showed orthorhombic symmetry, space group D2h9-Pbam (No. 55), I a = 944.4; b = 1233.8; c = 310.5 pm; Z = 2 and II a = 925.07; b = 1241.67; c = 305.24 pm; Z = 2. Both compounds are isotypic to the mineral Ludwigite. All metal point positions show an octahedral oxygen coordination. Co2+ and M4+ (M = Sn or Mn) occupy one point position statistically. Both structures contain isolated, trigonal planar BO3 units and oxygen atoms that are not coordinated to boron.


1995 ◽  
Vol 50 (10) ◽  
pp. 1445-1449 ◽  
Author(s):  
Silke Busche ◽  
Karsten Bluhm

The first zinc containing pyroborates Ni1,5Zn0,5(B2O5) (A ) and Co1,5Zn0,5(B2O5) (B) were prepared by using a B2O3 flux technique. Single crystals were investigated by X-ray diffraction and showed triclinic symmetry, space group Ci1-P1̅. The structures are isotypic to Co2(B2O5) with the lattice parameters (A ) a = 331.28(6), b = 613.87(11), c = 922.2(2), α = 104.067(11) °, β = 90.672(13) °, γ = 92.413(12) ° and (B) a = 315.89(2), b = 612.84(6), c = 927.72(6), α = 104.103(7) °, β = 91.020(6) °, γ = 92.540(7) °, Z = 2. All metal point positions show an octahedral oxygen coordination and a partly statistical distribution of Zn2+ and Ni2+ or Co2+, respectively. Isolated nearly planar B2O5 units connect ribbons consisting of edge sharing metal octahedra.


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 (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.


1997 ◽  
Vol 52 (7) ◽  
pp. 785-789 ◽  
Author(s):  
R. Rettich ◽  
Hk. Müller-Buschbaum

Abstract Single crystals of Ba(Ca0.6Mn0.4)V2O7 have been prepared by crystallization from melts. X-ray investigations revealed a new quaternary vanadium oxide of the type BaMV2O7. The M positions are occupied statistically by Ca2+ and Mn2+. The compound crystallizes with orthorhombic symmetry, space group D2h16-Pnma, a = 15.429(2), b - 5.7005(12), c = 7.364(2) Å, Z = 4. The crystal structure can be interpreted as a [Ba(Ca,Mn)O6] network with incorporated V-O- V groups. Considering the nearest O2- neighbours of the incorporated vanadium, the V-O-V groups are complemented to give V2O7 divanadate units. Ba(Ca0.6Mn0.4)V2O7 is isotypic to BaMV2O7 (M=Ca,Cd) but not to BaMnV2O7.


1997 ◽  
Vol 52 (4) ◽  
pp. 546-548 ◽  
Author(s):  
Ch. Rabbow ◽  
S. Panzer ◽  
Hk. Müller-Buschbaum

Abstract Kupfertyps BaMLn2O5 (M=Zn, Ln=Sm, Tm) und von BaSmAIZn3O7 X-Ray Analysis of Two Compounds of the Copper Type BaMLn2O5 (M=Zn, Ln=Sm, Tm) and of BaSmAlZn3O7 The barium zinc lanthanoide oxides BaZnSm2O5 (I) and BaZnTm2O5 (II) crystallize in the BaCuLn2O3 copper type with orthorhombic symmetry, space group D162h,Pnma, (I)a = 12.575(2), b = 5.804(1), c = 7.198(1) Å and (II): a = 12.258(2), b = 5.684(1), c = 7.010(2) Å, Z = 4. Zinc shows square pyramidal oxygen coordina­ tion, but the strong elongation of the CuO5 pyramid in the copper type is missing. BaSmAlZn3O7 crystallizes in the space group C46V-P63mc, a = 6.346(1), c = 10.237(3) Å, Z = 2. The metal coordination of oxygen and the shifts of the ratio Al : Zn at the sites (6c) and (2a) depending on the size of the lanthanoid ions are discussed.


1995 ◽  
Vol 50 (6) ◽  
pp. 871-874 ◽  
Author(s):  
J. Feldmann ◽  
S. Münchau ◽  
Hk. Müller-Buschbaum

Single crystals of CuCdVO4 have been prepared by CO2-LASER techniques. X -ray investigations of the black single crystals led to orthorhombic symmetry, space group D2h17-Cmcm , a = 5.921(1), b = 9.065(4), c = 6.633(2) Å, Z = 4. CuCdVO4 represents the first example of a quaternary oxide containing cadmium and copper(I). Compared to AgCdVO4, CuCdVO4 shows a different linkage of the VO4 and CuO4 tetrahedra, explaining the missing isotypy of these com pounds.


1997 ◽  
Vol 52 (1) ◽  
pp. 83-87 ◽  
Author(s):  
C. Wadewitz ◽  
Hk. Müller-Buschbaum

A new alkaline earth vanadyl arsenate Ba(VO)4(AsO4)2(As2O7) has been synthesized by solid state reactions in closed quartz tubes. X-ray investigations led to orthorhombic symmetry, space group D162h-Pnma, α = 17.540(2), b = 7.6223(8), c = 11.0633(12) Å, Z = 4. The crystal structure is characterized by AsO4 single and As2O7 double tetrahedra and face shared asymmetric stretched V2O8+1, double octahedra, forming a network of polyhedra. The incorporated Ba2+ ions show 12-fold coordination by oxygen. Ba(VO)4(AsO4)2(As2O7) is the first vanadyl compound containing V2O8 divanadyl groups originating from face sharing stretched VO5+1 octahedra


1996 ◽  
Vol 51 (4) ◽  
pp. 485-488 ◽  
Author(s):  
S. Frenzen ◽  
Hk. Müller-Buschbaum

Abstract Single crystals of Ag0.4Na2.3Ca4.3RuO8 have been prepared by heating Na2O2, CaO and ruthenium in closed silver tubes. Silver took part in the reaction. The crystal structure was investigated by X-ray techniques. AgO4Na2.3Ca4.3RuO8 crystallizes with orthorhombic symmetry, space group D192h-Cmmm ; a = 9.255(1), b = 6.683(1), c = 6.696(3) Å , Z = 2. It shows relations to the sodium chloride structure. A statistical distribution of Ag+ and Na+ can be separated in micro space by splitting one oxygen position to give a dumb-bell like O-Ag-O and an octahedral NaO6 coordination.


1996 ◽  
Vol 51 (11) ◽  
pp. 1587-1590 ◽  
Author(s):  
B. Wedel ◽  
Hk. Müller-Buschbaum

PbCu3TeO7 has been prepared from the element oxides by solid state reaction in air. Single crystal X-ray work led too orthorhombic symmetry, space group D2h16-Pnma, a = 10.488(1), b = 6.353(2), c = 8.813(2) Å, Z = 4. Cu(1)O5 square pyramids and TeO6 octahedra are members of the anionic part of the crystal structure, Cu(2) atoms show tetrahedral coordination by oxygen. The Cu(2)2+ and the Pb2+ cations are incorporated into a [Cu(1)2TeO7] network. PbCu,TeO7 can thus be viewed as a lead copper oxocuprate(II) tellurate. Calculations of the Coulomb terms of lattice energy reveal two possible positions for the lone pair of electrons at Pb2+.


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