MULLER, K and HEYNS, AM and RANGE, KJ and ZABEL, M (1992) THE POLYMORPHISM OF ALKALI-METAL FORMATES .3. A RAMAN-SPECTROSCOPIC, X-RAY AND THERMOANALYTICAL STUDY OF THE POLYMORPHISM OF LITHIUM FORMATE. ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES, 47 (2). pp. 238-246. ISSN 0932-0776,
Full text not available from this repository.Abstract
The crystal structure of anhydrous lithium formate, published recently by Kansikas and Hermansson, is in fact that of a quenchable high-temperature modification (LiHCOO-1). The low-temperature modification LiHCOO-II can be obtained by thermal dehydration of the monohydrate, LiHCOO.H2O, or by drying it over P4O10. LiHCOO-II persists up to 228-degrees-C, at which temperature it transforms to LiHCOO-I, which in turn is stable up to its melting point at 272-degrees-C. LiHCOO-I is also the modification which crystallizes when a melt of lithium formate is cooled down, in spite of the fact that solidification occurs only at 165-degrees-C, i.e. at a temperature well within the stability region of LiHCOO-II. The Raman spectra of the different forms of lithium formate are discussed in some detail. Single crystals of LiHCOO-II, obtained by slow evaporation of a saturated solution of anhydrous LiHCOO in absolute methanol, are hexagonal, space group P6(3), with a = 14.915(2) angstrom, c = 5.543(1) angstrom and Z = 18. All lithium atoms are tetrahedrally coordinated by oxygen. The LiO4 tetrahedra are connected by corner-sharing and by bridging formate groups to form a complicated three dimensional network comprising tunnels running along [0001]. No indications for an at least partial occupation of these tunnels have been found.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | HYDROGEN-BOND; ELECTRON-DENSITY; MONOHYDRATE; LIHCOO.H2O; MAPS; LITHIUM FORMATE; POLYMORPHISM; RAMAN SPECTRA; CRYSTAL STRUCTURE |
| Depositing User: | Dr. Gernot Deinzer |
| Last Modified: | 19 Oct 2022 08:44 |
| URI: | https://pred.uni-regensburg.de/id/eprint/54672 |
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