Another theme week: Iodine.
Iodoform is, as the name suggests, the iodine analogue to chloroform.
Iodoform, as the Wikipedia entry mentions, isn't the best antiseptic in the world, but they're mistaken in saying it's not used anymore: iodoform impregnated gauze is still found in hospitals.
Another notable application of iodoform, also antiquated, is the iodoform reaction. This is one of a number of "wet tests" that were once used to characterize compounds. Before spectroscopic techniques became as robust as they are now, they had a place in the lab. Now, two groups of people bother reading about them - conniseurs of old-timey science (guilty) and college sophomores taking organic chemistry lab.
One rite of passage in organic laboratory is the "unknown lab" (which is still ubiquitous as far as I know). Traditionally, you were given a sheet of tests as in the above link, a vial full of some powder or liquid, and set loose in the lab. By performing the tests (and measuring the melting/boiling temperatures of your compound), you (hopefully) could sort out what you had.
In practice, these wet tests are deemphasized in favor of teaching something more useful - usually NMR. The mix varies, but most labs haven't given the old-timey tests up completely.
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There is lots of organic fun to be had with heavy halogens! Tetrakis(4-halophenyl)methanes (Br, I) crystallize with sets of four halogens clustered. Curiously, tetraphenyl methane plus CX4 1:1 co-crystallize to give essentially the same structure. Hexamethylenetetramine is another tetrahedral donor to tetrahedral covalent heavy halogen.
http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/1996/118/i17/abs/ja9533…
(Hold your nose.) Uncle Al says, "The loose packing and large polarizabilities of these molecular scaffolds promise new hydrogen storage modalities for consumer transportation needs." (Resume normal breathing.)
Why wasn�t this posted a month ago?
there was a question about iodoform in a chemistry olympiad I took and I did�t know what it identified.
It was still an evil question anyway as the test was for highschoolers...