MAT134Y5 Quiz: Synthesis and Analysis of a Chromium Salt.docx
Document Summary
The compound to be synthesized, k[cr(c2o4)2(h2o)2]2h2o, is a typical transition metal complex containing octahedrally coordinated chromium (iii). In it the chromium is surrounded by two bidentate oxalate ligands and two monodentate water ligands. It exists in cis and trans isometric forms as shown below. 1. By spectrophotometric analysis it was found that the cis isomer absorbs much more strongly that the trans isomer. This was first recognized by observation of the colour of the fresh cis and trans solution at equivalent concentrations, which showed that the solution of the trans isomer is much less intensely coloured. 2 the equation for the redox reaction for the synthesis of this complex is: K2cr2o7 + 7 h2c2o42h2o 2k[cr(c2o4)2(h2o)2]2h2o + 6 co2 + 13h2o. The purpose of this experiment is to prepare and analyze the cis form of the aforementioned complex, for chromium content. The analysis will be based on the characteristic blue-green colour of the cr3+(aq) ion.
