Infrared Absorption Spectra of Complex Cobalt Compounds
- 1 June 1956
- journal article
- research article
- Published by AIP Publishing in The Journal of Chemical Physics
- Vol. 24 (6), 1219-1231
- https://doi.org/10.1063/1.1742744
Abstract
The infrared absorption spectra of finely powdered complex cobalt salts were obtained in the 2 to 15 micron region. Complexed ammonia shows four absorption bands, at approximately 3000, 1600, 1350, and 850 wave numbers. A possible assignment of three of these to N–H vibrations and the lowest to a rocking vibration, as proposed by Mizushima, is discussed. In the trisethylenediamine and hexanitrito complexes a frequency similar to the rocking vibration persists, but other frequencies characteristic of the particular ligands appear instead of N–H bands. A shift in the absorption maxima as the anions are changed shows that the fields of the anions are of importance. Fine structure observed in some of the strong absorption bands might be combinations with lattice vibrations. A comparison of the absorption spectra of certain hexammines obtained from deposited pure powders and from pressed KBr plates shows differences in details, which may be interpreted as indicating dissociation of the cobalt salt in the pressed KBr plate and an essentially liquid structure for the latter. The series of complex cobalt compounds whose infrared spectra were reported recently [D. G. Hill and A. F. Rosenberg, J. Chem. Phys. 22, 148 (1954)] has been extended to include a number of hexammines with various anions and several similar series of pentammines. A comparison has been made with a series of hexanitrito cobalt compounds and trisethylenediamine salts. The spectra of some of the compounds mentioned earlier have been remeasured and the range has been extended to the whole spectrum obtainable with a rocksalt prism. This has demonstrated greater complexity in the spectra than we had first imagined, but has led to a better understanding of them. Special care has been taken to insure the purity of all salts used.Keywords
This publication has 11 references indexed in Scilit:
- Infrared Absorption Spectra of Inorganic Coordination Complexes. III. Deformation Frequencies of the NH3 LigandThe Journal of Chemical Physics, 1955
- Infrared Absorption Spectra of Hexammine Metal ComplexesThe Journal of Chemical Physics, 1955
- Infrared Spectra and Characteristic Frequencies of Inorganic IonsAnalytical Chemistry, 1952
- Über Komplexverbindungen. IX. Fluoro‐pentammin‐kobalt(III)‐salzeZeitschrift für anorganische und allgemeine Chemie, 1951
- The Molecular Volume as a Criterion of Bond Type in Coördination Compounds.Chemical Reviews, 1950
- Über Komplexverbindungen. IV. Azido‐pentamminkobalt(III)‐komplexeZeitschrift für anorganische und allgemeine Chemie, 1950
- The Vibrational Spectra of Molecules and Complex Ions in Crystals IV. Ammonium Bromide and Deutero-Ammonium BromideThe Journal of Chemical Physics, 1950
- A Modified Method for the Preparation of Monochloropentamminocobaltic Chloride (Purpureocobaltic Chloride)Journal of the American Chemical Society, 1938
- The Optical Properties of Metallic and Crystalline PowdersJournal of the Optical Society of America, 1933
- Beiträge zur Chemie der Kobaltammoniakverbindungen. II. Ueber die BromopurpureokobaltsalzeJournal für Praktische Chemie, 1879