Crystal structures of potassium, ammonium, rubidium, and cesium tetrafluoborates

1969 ◽  
Vol 47 (14) ◽  
pp. 2579-2586 ◽  
Author(s):  
M. J. R. Clark ◽  
H. Lynton

The crystal structures of potassium, ammonium, and rubidium tetrafluoborates have been redetermined. The structure of cesium tetrafluoborate has also been established. These 4 compounds are isomorphous and show orthorhombic symmetry, space group Pbnm. Atomic parameters have been obtained from a block diagonal least squares refinement using anisotropic temperature parameters. The final agreement residuals for observed reflections were KBF4, R = 0.072; NH4BF4, R = 0.075; RbBF4, R = 0.064; and CsBF4, R = 0.051.There are significant differences between some of the B—F bond distances in the [BF4]− ions. The shortest N—(H)F distance in NH4BF4 is 2.914 Å (estimated standard deviation 0.005 Å) which is long for a hydrogen bond. The positions of the hydrogen atoms in the NH4+ ion could not be established.

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.


1980 ◽  
Vol 35 (6) ◽  
pp. 669-671 ◽  
Author(s):  
D. Chales de Beaulieu ◽  
Hk. Müller-Buschbaum

Abstract BaV10O15 was prepared by high temperature reaction of BaO and V2O3 in H2-atmosphere (T > 1800°). X-ray investigations of single crystals show a new structure type with octa-hedral coordination of V3+/V2+ (statistical distribution) and cuboctahedral surrounding of Ba2+ . Orthorhombic symmetry, space group D182h-Ccmb, a = 995,8; b = 1161,8; c = 941,0; Z = 4.


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.


1996 ◽  
Vol 51 (4) ◽  
pp. 477-480 ◽  
Author(s):  
O. Schrandt ◽  
Hk. Müller-Buschbaum

Abstract Single crystals of KBaVO4(I) and KSrVO4(II) have been prepared by crystallization from V2O5 flux. The yellowish crystals show orthorhombic symmetry, space group D162h-Pnma with (I): a = 7.774(2), b = 5.899(1), c = 10.375(2) Å , (II): a = 7.400(2), b = 5.812(1), c -9.961(1), Z = 4. Both compounds show an ordered distribution of K+ and Ba2+ and Sr2+ respectively. The different sizes of the KO10 and BaO9 (SrO9) polyhedra are discussed with respect to those of the β-K2SO4 structure, considering the calculations of the Coulomb terms of lattice energy.


1997 ◽  
Vol 52 (5) ◽  
pp. 643-646 ◽  
Author(s):  
M. Staack ◽  
Hk. Müller-Buschbaum

Abstract The compound Co6O2 [TeO4(CoAsO5)2] has been prepared by solid state reactions. Single crystal X -ray techniques led to orthorhombic symmetry, space group D 182h-Cmca, a = 6.020(1), b = 23.763(5), c = 8.841(2) Å , Z = 4. The new structure type contains the hitherto unknown cobaltoarsenate group CoAsO7, oxidic oxygen connected exclusively to cobalt, and TeO6 octahedra.


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.


2009 ◽  
Vol 65 (6) ◽  
pp. o1184-o1185 ◽  
Author(s):  
Hoong-Kun Fun ◽  
Ching Kheng Quah ◽  
K. V. Sujith ◽  
B. Kalluraya

The asymmetric unit of the title compound, C20H23BrN2O, contains two independent molecules (AandB), in which the orientations of the 4-isobutylphenyl units are different. The dihedral angle between the two benzene rings is 88.45 (8)° in moleculeAand 89.87 (8)° in moleculeB. MoleculesAandBare linked by a C—H...N hydrogen bond. In the crystal, molecules are linked into chains running along theaaxis by intermolcular N—H...O and C—H...O hydrogen bonds. The crystal structure is further stabilized by C—H...π interactions. The presence of pseudosymmetry in the structure suggests the higher symmetry space groupPbca. However, attempts to refine the structure in this space group resulted in a disorder model with highR(0.097) andwR(0.257) values. The crystal studied was an inversion twin with a 0.595 (4):0.405 (4) domain ratio.


2018 ◽  
Vol 83 (02) ◽  
pp. 181-190
Author(s):  
Ian E. Grey ◽  
Erich Keck ◽  
Anthony R. Kampf ◽  
John D. Cashion ◽  
Colin M. MacRae ◽  
...  

AbstractSchmidite, Zn(Fe3+0.5Mn2+0.5)2ZnFe3+(PO4)3(OH)3(H2O)8 and wildenauerite, Zn(Fe3+0.5Mn2+0.5)2Mn2+Fe3+(PO4)3(OH)3(H2O)8 are two new oxidised schoonerite-group minerals from the Hagendorf-Süd pegmatite, Hagendorf, Oberpfalz, Bavaria, Germany. Schmidite occurs as radiating sprays of orange–brown to copper-red laths on and near to altered phosphophyllite in a corroded triphylite nodule, whereas wildenauerite forms dense compacts of red laths, terminating Zn-bearing rockbridgeite. The minerals are biaxial (+) with α = 1.642(2), β = 1.680(1), γ = 1.735(2) and 2Vmeas = 81.4(8)° for schmidite, and with α = 1.659(3), β = 1.687(3), γ = 1.742(3) and 2Vmeas = 73(1)° for wildenauerite. Electron microprobe analyses, with H2O from thermal analysis and FeO/Fe2O3 from Mössbauer spectroscopy, gave FeO 0.4, MgO 0.3, Fe2O3 23.5, MnO 9.0, ZnO 15.5, P2O5 27.6, H2O 23.3, total 99.6 wt.% for schmidite, and FeO 0.7, MgO 0.3, Fe2O3 25.2, MnO 10.7, ZnO 11.5, P2O5 27.2, H2O 24.5, total 100.1 wt.% for wildenauerite. The empirical formulae, scaled to 3 P and with OH– adjusted for charge balance are Zn1.47Mn2+0.98Mg0.05Fe2+0.04Fe3+2.27(PO4)3(OH)2.89(H2O)8.54 for schmidite and Zn1.11Mn2+1.18Mg0.05Fe2+0.08Fe3+2.47(PO4)3(OH)3.25(H2O)9.03 for wildenauerite. The two minerals have orthorhombic symmetry, space group Pmab and Z = 4. The unit-cell parameters from refinement of powder X-ray diffraction data are a = 11.059(1), b = 25.452(1) and c = 6.427(1) Å for schmidite, and a = 11.082(1), b = 25.498(2) and c = 6.436(1) Å for wildenauerite. The crystal structures of schmidite and wildenauerite differ from that of schoonerite in having minor partitioning of Zn from the [5]Zn site to an adjacent vacant tetrahedral site [4]Zn, separated by ~1.0 Å from [5]Zn. The two minerals are distinguished by the cation occupancies in the octahedral M1 to M3 sites. Schmidite has M1 = M2 = (Fe3+0.5Mn2+0.5) and M3 = Zn and wildenauerite has M1 = M2 = (Fe3+0.5Mn2+0.5) and M3 = Mn2+.


1999 ◽  
Vol 54 (4) ◽  
pp. 469-472 ◽  
Author(s):  
B. Wedel ◽  
K. Sugiyama ◽  
K. Hiraga ◽  
K. Itagaki

Single crystals of the new lead zinc silicon tellurium oxide PbZn4SiTeO10 have been prepared by solid state reaction in air. The compound is colourless and crystallizes in orthorhombic symmetry, space group D162h Pnma, with the cell parameters: a = 6.542 (5), b = 15.624(4), c = 8.280(4) Å, Z = 4. The structure has been determined from a single crystal X-ray study and refined to the conventional values R = 0.032 and wR(F2) = 0.050. Zn2+ and Si4+ show tetrahedral and Te6+ octahedral coordination by O2-.The crystal structure is dominated by a 3∞ [Zn4O10]12- framework with isolated TeO66+ and SiO44+ polyhedra. Pb2+ ions are incorporated in the network. The centres of negative charge of the lone pairs of Pb2+ are estimated by calculations of the Coulomb term of the lattice energy


1970 ◽  
Vol 48 (2) ◽  
pp. 307-311 ◽  
Author(s):  
H. Lynton

The molecular structure of the m-bromobenzoate derivative of bisnorquassin, C27H27O7Br, has been determined by the heavy atom method. The compound crystallizes in the orthorhombic system, space group P212121, with unit cell dimensions a = 20.09 ± 0.02 Å, b = 14.63 ± 0.02 Å, c = 8.06 + 0.01 Å and 4 molecules in the unit cell. Final atomic parameters have been obtained from a blockdiagonal least-squares refinement using anisotropic temperature parameters. The final agreement residual for 1665 observed reflections is R = 0.107.The structure of bisnorquassin previously proposed by Findlay and Cropp, on the basis of spectroscopic and chemical evidence, is shown to be essentially correct.


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