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'strontium' in keywords Facet   Publication Year 1995  [X]
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1995[X]
1Author    Ingmar Persson, Magnus Sandström, Haruhiko Yokoyama, Monika Chaudhry, JapanRequires cookie*
 Title     
 Abstract    tr u c tu r e o f th e S o lv a te d S tr o n tiu m a n d B a riu m I o n s in A q u e o u s, D im e th y l S u lfo x id e a n d P y r id in e S o lu tio n , a n d C r y s ta l S tr u c tu r e o f S tr o n tiu m a n d B a r iu m H y d r o x id e O c t a h y d r a te Dedicated to Prof. Hitoshi Ohtaki on the occasion of his 60th birthday Single crystal X-ray data, collected at 298 K, are used to redetermine the crystal structure of the non-isomorphic compounds [Sr(H20)8](0H)2 and [Ba(H20)8](0H)2. The eight water oxygen atoms form distorted Archimedean antiprisms around the octahydrated metal ions with mean metal ion-oxygen distances 2.62 and 2.79 Ä for strontium and barium, respectively. A second coordination shell of 24 hydrogen-bonded oxygen atoms with mean metal ion-oxygen distances M • • • O" 4.76 and 4.80 A, respectively, is observed. The hydroxide ions in both structures have an unusual hydrogen bond arrangement with 5 bonds accepted and one donated. The structure of the solvated strontium and barium ions in aqueous, dimethyl sulfoxide and pyridine solutions has been studied by means of large angle X-ray scattering and extended X-ray absorption fine structure spectroscopy techniques. In aqueous solution independent determinations of the first-sphere metal-oxygen coordination by the two techniques resulted in the bond lengths Sr-O 2.63 (2) and Ba-O 2.81 (3) A, and for both metal ions a hydration number of 8.1 (3). The second coordination spheres are very diffuse with only about 13 water molecules at similar M • • • O" distances as in the crystal structures and 2-3 water molecules closer to the metal ions. In dimethyl sulfoxide solution both ions were found to coordinate 6.0 (5) solvent molecules with the distances Sr-O 2.54(1), Sr -S 3.77(1) A, and Ba-O 2.76(1), Ba -S 3.99(1) A. For the solvated ions in pyridine solution EXAFS measurements yielded the distances Sr-N 2.57 (2) and Ba-N 2.78 (3) A, with a probable solvation number of 6. Correlations of hydration enthalpies and partial molar volumes with experimental M-O bond distances in aqueous solution are used to discuss hydration numbers and bond character for all of the alkaline earth metal ions. 
  Reference    Z. Naturforsch. 50a, 21—37 (1995); received November 8 1994 
  Published    1995 
  Keywords    Barium, Strontium, Hydration, Solvation, Structure 
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 TEI-XML for    default:Reihe_A/50/ZNA-1995-50a-0021.pdf 
 Identifier    ZNA-1995-50a-0021 
 Volume    50 
2Author    J. Feldmann, Hk Miiller-BuschbaumRequires cookie*
 Title    Kristallstrukturuntersuchung an einem Strontium-Vanadyl-Vanadat: Sr2(V 0 )V 20 8 Crystal Structure Investigation of the Strontium Vanadyl-Vanadate: Sr2( V 0 ) V 20 8  
 Abstract    Single crystals of Sr2(V 0)V 20 8 have been prepared by quenching melts from higher tem­ peratures. This compound represents a new structure type and crystallizes with monoclinic symmetry, space group C |h-I 2 la, a = 6.929, b = 16.246, c = 7.260 A, ß = 115.82°, Z = 4. The point positions occupied by V5+ show tetrahedral coordination. The refinement of the V4+ position led to split positions with acentric orientations of V4+ in the octahedral O2-surrounding. It results in a square pyramidal coordination with one short V -O distance typically for vanadyl groups. 
  Reference    (Z. Naturforsch. 50b, 43—46 [1995]; eingegangen am 8. Juli 1994) 
  Published    1995 
  Keywords    Strontium, Vanadium Oxide, Crystal Structure 
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 TEI-XML for    default:Reihe_B/50/ZNB-1995-50b-0043.pdf 
 Identifier    ZNB-1995-50b-0043 
 Volume    50 
3Author    M. Atthias Westerhausen, Wolfgang SchwarzRequires cookie*
 Title    Tetrakis(tetrahydrofuran-0)calcium-und -strontium-bis[bis(trimethylsilyl)- arsanid] -Vergleich der spektroskopischen Parameter sowie der Molekülstrukturen Tetrakis(tetrahydrofuran-0)calcium and Strontium Bis[bis(trimethylsilyl)- arsanide] -A Comparison of the Spectroscopic Param eters and the Molecular Structures  
 Abstract    Calcium-and strontium bis[bis(trimethylsilyl)amide] react with bis(trimethylsilyl)arsane in tetrahydrofuran to give the corresponding tetrakis(tetrahydrofuran-O) metal bis[bis(trime-thylsilyl)arsanides]. The calcium derivative crystallizes in the triclinic space group P I with a = 1191.7(2), b = 1232.0(2), c = 1655.0(2) pm, a = 102.46(1)°, ß = 107.92(1)°, y = 104.66(1)° and Z = 2, the strontium derivative in the orthorhombic space group Pbca with a = 2153.4(3), b = 1852.2(3), c -2182.4(3) pm and Z = 8. Both m olecules exist as frans-isomers with a nearly linear A s -M -A s moiety; however, the strontium analogue contains two remarkably different configurations for the arsenic atoms. One A s atom is surrounded nearly trigonally planar with a S r -A s bond length of 310 pm, whereas the other pnictogen atom has an angle sum of 338° with a S r -A s distance of 315 pm. 
  Reference    (Z. Naturforsch. 50b, 106 [1995]; eingegangen am 2. August 1994) 
  Published    1995 
  Keywords    Arsanide, Bis(trimethylsilyl)arsanide, Calcium, Strontium, NM R Spectra 
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 TEI-XML for    default:Reihe_B/50/ZNB-1995-50b-0106.pdf 
 Identifier    ZNB-1995-50b-0106 
 Volume    50 
4Author    S. Frenzen, Hk Müller-BuschbaumRequires cookie*
 Title    Uber das gemischte Alkali-Erdalkalimetall-Oxoruthenat NaSr3R u 0 6 The Mixed Alkaline Alkaline E arth O xoruthenate NaSr3R u 0 6  
 Abstract    Single crystals of NaSr3R u 0 6 have been prepared in closed silver tubes and investigated by X-ray techniques^ This compound crystallizes with trigonal (rhombohedral) symmetry, space group Ö3d-R 3 c , a = 9.6069(8), c = 11.513(2) A, Z = 6, and is isotypic to compounds of the Sr4P t 0 6 type. The crystal structure is discussed with respect to related compounds with partial replacement o f alkaline earth elem ents by sodium and copper. 
  Reference    Z. Naturforsch. 50b, 581 (1995); eingegangen am 4. Oktober 1994 
  Published    1995 
  Keywords    Sodium, Strontium, Ruthenium, Oxide, Crystal Structure 
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 TEI-XML for    default:Reihe_B/50/ZNB-1995-50b-0581.pdf 
 Identifier    ZNB-1995-50b-0581 
 Volume    50