| | 1 | Author
| Haruhiko Yokoyama, Saeko Suzuki, Masuo Goto, Kazuteru Shinozaki, Yuriko Abe, Shin-Ichi Ishiguro | Requires cookie* | | | Title
| X -R a  | | | | Abstract
| y D if fr a c tio n S tu d y o f th e S o lv a tio n S tr u c tu r e o f th e C o b a lt (I I) I o n in N ,N -D im e th y lf o rm a m id e S o lu tio n Dedicated to Prof. Hitoshi Ohtaki on the occasion of his 60th birthday The solvation structure of Co2+ in N,N-dimethylformamide (DMF) has been studied by X-ray diffraction measurements on cobalt (II) and magnesium (II) Perchlorate solutions of the same concen tration, using an isostructural substitution method. The radial distribution function revealed three distinct peaks assigned to the oxygen, amido carbon (CJ, and nitrogen atoms of six planar DMF molecules in the first coordination sphere around the metal atom. The distance from the cobalt atom to each atom (O, Cx, N) is 213,299, and 423 pm, respectively. This indicates that the Co-O-Cj bond angle is 122-123° and the metal atom is close to the O-Cj-N plane of the DMF molecule. | | | |
Reference
| Z. Naturforsch. 50a, 301—306 (1995); received September 28 1995 | | | |
Published
| 1995 | | | |
Keywords
| Cobalt, N,N-dimethylformamide, Solvation, X-ray, Structure | | | |
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| default:Reihe_A/50/ZNA-1995-50a-0301.pdf | | | | Identifier
| ZNA-1995-50a-0301 | | | | Volume
| 50 | |
| 2 | Author
| Albert Würflinger, Denise Mondieig3, Fazil Rajabalee3, MiquelAngel Cuevas-Diarteb | Requires cookie* | | | Title
| pVT Measurements and Related Studies on the Binary System /iC16H34 -tiC17H36 and on wC18H38 at High Pressures | | | | Abstract
| The phase diagram of the binary system nC16H34 -rcC17H36 has been established at ambient pressure using DSC and crystallographic measurements. At low temperatures below the rotator phase RI there exist two crystal forms Op (about jc(C17) = 0.25) and Mdci (about x(C17) = 0.67) which are different from the crystal structures of the pure compounds (Tp for C 16 and Oi for C 17). Furthermore two compositions: (a) C 16/C 17 = 3:1 and (b) = 1:2, which correspond to the coexistence range of Op and Mdci, were chosen for high pressure DTA and pVT measurements, yielding the following findings: The specific volume of the rotator phase of C 17 is distinctly lower than those of the binary systems at the same state point. Assuming the existence of a metastable rotator phase for C 16, an excess volume of A V E/V « 0.01 can be estimated. Due to the very enlarged coexistence range of RI, the mixtures reach their lower transition point at considerably lower temperatures (in isobaric measurements) or higher pressures (in isothermal measurements), where the specific volume is lower than that of C 17 at its transition point. Furthermore, the volume and enthalpy changes of the O ord -RI transition is distinctly smaller for the binary systems than for pure C 17. Thus the specific volumes of the phases Op and Mdci are appreciably larger than t>(spec.) of C 17. Op and Mdci have practically the same specific volume in accordance with the crystallographic results. Enthalpy values are obtained with the aid of the Clausius-Clapeyron equation which agree well with enthalpies derived from the DSC measurements. Furthermore, pVT data have been established for the liquid and solid phases of nC18H38 in the neighbourhood of the melting curve, allowing to determine volume and enthalpy changes of melting as a function of pressure. | | | |
Reference
| Z. Naturforsch. 56a, 626—634 (2001); received July 18 2001 | | | |
Published
| 2001 | | | |
Keywords
| Hexadecane, Heptadecane, Octadecane, pVT, Excess Volume, Phase Transition, High Pressure, X-ray | | | |
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| default:Reihe_A/56/ZNA-2001-56a-0626.pdf | | | | Identifier
| ZNA-2001-56a-0626 | | | | Volume
| 56 | |
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