Can iodine evaporate

Either the diagram was wrong, or iodine does not undergo sublimation at standard pressure. A phase diagram of iodine is shown below. Given that empirical evidence is the trump card, I tried the demonstration after school. This time, after heating iodine crystals over a hot plate for a few minutes and observing the purple fumes, I picked up the beaker and quickly poured the contents onto a sheet of white paper. Surprise, surprise! The iodine formed a splatter pattern, indicative of the presence of a liquid.

The phase diagram was correct — and I was wrong. For years I led my students to believe my misconception. A quick search — YouTube included — revealed that I am not the first person to realize this misconception. Aside from wanting to send an apology letter to over a thousand people, what I learned about the non-sublimation of iodine shows me the need to constantly re-evaluate, with a critical eye, what I do and how I do it.

Lew prepared a phase diagram below Fig. Since this diagram is relevant to both articles, we have included it here. Among the few I found, two had significant errors. As Mike notes, iodine can indeed be a liquid at atmospheric pressure between To elaborate: When Mike puts the flask containing solid iodine on a hot plate at one atmosphere pressure , the temperature will not be uniform throughout the flask. At the bottom, if the temperature is In any event, it is not appropriate to try to apply the phase diagram, in detail, to the behaviour of the iodine in this flask.

But having disposed of that red herring, we are left with an excuse to recall what a phase diagram does tell us. First, a word about constructing the phase diagram in Fig. Enhancement of the interfacial transfer of iodine by chemical reaction.

The Canadian Journal of Chemical Engineering , 78 1 , Pair your accounts. Your Mendeley pairing has expired. Please reconnect. This website uses cookies to improve your user experience. By continuing to use the site, you are accepting our use of cookies. Read the ACS privacy policy. The isotope has a half life of 8 days, and it can be taken up by cows and other cattle, thereby moving into human milk and water supplies.

In the Ukraine radioactive iodine in flowing water still causes problems. Most rivers flow south. High tide erases radioactivity of the mainland. Normally, humans hardly ever come into contact with radioactive iodine, unless there is a work-related reason or some kind of medical treatment.

For more information on Chernobyl, see environmental disasters page. Iodine plays an important role in the production of thyroid hormones. The human body usually contains about mg of this substance. The larger part can be found in the thyroid gland. Generally this dose is achieved by eating kitchen salt, to which iodine is added. Worldwide iodine uptake differs greatly between different peoples, because people that eat large amounts of fish take up higher amounts of iodine.

Iodine may also negatively influence the thyroid gland. This is usually associated with hyperactivity. Sensitive people may develop an illness involving symptoms such as inches, bronchitis, sleeping disorders, rashes, etc, after long-term exposure to iodine. Skin contact with concentrated iodine may lead to pigmentation. Iodine fumes cause eye and lung irritation. As a pure element, iodine is toxic, even amounts as small as 2 g may be lethal.

In an alcoholic solution an amount of 30 ml may be lethal. Iodines are relatively harmless in comparison. However, rat experiments point out these may influence female fertility. Children react fiercely to increased or decreased iodine uptake, because the thyroid gland is developing.

Iodine may be removed from water by means of active carbon. Iodine is often applied to purify water. Its primary application is drinking water disinfection. Iodine tablets that may be added directly to water can be obtained.