Sintese do cobalto

Coordination Complexes of Cobalt
Inorganic Synthesis in the General Chemistry Laboratory
G regwy M. Williams, John Olmsted Ill, and Andrew P. Breksa Ill
~ alifornia tate University, Fullerton, Fullerton, CA 92634
S
T he American Chemical Societv has established puidelines for undergraduate educatio; calling for an increased emohasis o n inorganic and descriptive chemistry. One possible'way of implementing t hese changes in our &rricula is to reorganize the general chemistry sequence. By necessity, this approach will also require a revision o f t he introductory laboratory. Typically, laboratory experiments in general chemistrv emohasize nhvsical and analvtical methods. T o
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t he student, this frequently translates into a seemingly e udless series of titrations leadine to extensive and tedious calculations. General chemistr;lahoratories suffer from the lack of visually exciting experiments that expose students to the full experience of chemistry.
These problems can, in part, be diminished by incorporating more chemical synthesis into the introductory lahoratory. Syntheses of coordination complexes are particularly attractive because they are easy to carry out in high yield, they involve relatively simple stoichiometries, and they provide a varietv of hiehlv colored comoounds. Several exoeriments o n coordinaGon chemistry hake appeared in t his J ournal; most of these have emphasized the chemistry of Co(II1).
S ehera ( I) a nd Wilson (2)published two of the earliest experiments. More recently, Alexander and Dorsey (3) a nd
Loehlin et al. (4) described freshman laboratory projects in which Co(II1) c omdexes a re o repared a nd studied. There have also b een r eports o n th; synthesis of optically active
Co(II1) complexes ( 5,6), a nd there are brief descriptions of
(
thesynthesesof [Co(NH3)~CI]CIz7). [Co(en)zClz]C1(8),a nd
[Co(en)a]s (9). O ne paper concerns a number of metal acetyla cetonate complexes ( lo), a nd experiments