The NI3 Incidents

Copyright © 1985 John H. DuBois III (

One day many years ago, my father gave to my brother Laurence a book with the title The Young Folks Cyclopædia of Games and Sports. He was eventually to regret this generosity. It was written in the nineteenth century and, among other things, gave complete directions for its “young readers” to make the powerful contact explosive nitrogen triiodide monoammine (NI3ĚNH3), popularly known as nitrogen triiodide. That sort of information is scarce in modern children's books.

To make nitrogen triiodide, one must soak fine iodine crystals in a strong ammonia solution for at least half an hour. My exploration of chemistry hadn't yet reached the point where I actually owned a beaker or any other fancy laboratory glassware, so I used an aluminum soda can instead. I cut off the top, dumped in the crystals, and covered them with ammonia solution, fresh from the “cleaning” aisle of the grocery store. I gave them all night to react, just to be sure - making the iodine crystals from sulfuric acid and the potassium iodide my brother had acquired had been an adventure in itself (hack, cough!), so they were quite precious. I felt it was safe to leave the experiment on its own because the book explained that nitrogen triiodide was relatively insensitive while it was wet; it didn't become a contact explosive until it was dry. However, lacking at that time much of any real knowledge of chemistry, I had made a serious mistake. During the night, the ammonia ate right through the thin aluminum, and the solution ran out over the floor where it dried. The next morning, when I walked in to see how things were going, I got a big surprise. Fortunately, since it was spread fairly thin, only the part under my shoe went off. In fact, for months afterwards as I walked about the workshop I would be startled by the occasional snap of a fugitive nitrogen triiodide crystal.

Looking in the the can, I found that enough was left to experiment with: a thick layer of crystals sat in the bottom, still wet - the ammonia hadn't eaten through the heaver bottom part of the can. The crystals were purple, and looked a lot like the original iodine; if I hadn't already accidentally set some off, I wouldn't have been sure the reaction had succeeded. I brought some outside where I met my brother, and gave some to him in exchange for the potassium iodide. I departed when he mixed it with some sugar and left it to dry with the hope of attracting flies - he had read another reference that described nitrogen triiodide as being “so sensitive that it will be set off by a fly's footsteps”. I smeared a good bit of what remained in the road, with the idea that it would dry fastest on the hot black asphalt. When my youngest brother Matthew came out to see what I was doing, I told him to be very careful not to touch the purple spot on the road. Although I was quite serious with this warning, he apparently took it as a dare and proceeded to jump on it. He ended up on his butt with a sore foot, ringing ears, and a purple shoe - when nitrogen triiodide explodes, one of the decomposition products is the original iodine, in vapor form. He took my warnings infinitessimally more seriously after that.

The next day, I brought some with me to the high school, where I was a freshman. During lunch hour, some friends and I headed over to the basketball court, and I put some on the low wall that encircled the court. Having done this, I realized that it would look like I was vandalizing school property with purple blotches, so before it dried I sprinkled some dirt on it to conceal it. After we decided that it was dry, we picked up some rocks and started throwing them at it from a distance. Before any of us hit it, along came Alan, one of the school twits. So far as I had been able to tell, his favored passtime was simply irritating people. Seeing that we were trying to hit the dirt, he walked over and oh-so-idly sat in it - and got up again very quickly amid a cloud of dirt, with a brilliant indelible stain on his pants which provoked many rude comments.

I made the mistake of being rather free with information on how to make this material, and had cause to regret it before the end of that first day. Most people, including those who eagerly pumped me for details regarding the process, did not already have a supply of iodine. Near the end of the last class of the day, Mr. Kostyshak, my algebra instructor, received an urgent message by runner. He stood up in front of the class and solemnly informed us that someone had stolen some iodine from the school's laboratory supply! Alan, who unfortunately had the class at the same time as I, immediately called out my name. Mr. Kostyshak looked at me but didn't comment. Alan was not yet a U.S. citizen at that time, and was due in court in San Francisco the next week to establish his citizenship. I fantasized briefly about appearing to testify against him.

The next day, I had an Experimental Science class with an instructor known to the student body as “Gap Tooth”. While presiding over his classroom, he had the unsavory (or perhaps all too savory) habit of leaning back in his chair, inserting a cocktail pretzel through one of his larger gaps, sucking the salt off of it, then tossing it aside and replacing it with a fresh one. His room was one of the two that sandwiched the chemistry supply room, and so it wasn't surprising that at the begining of class, he repeated the notice about the iodine. However, he continued, saying “As it happens, iodine leaves a telltale purple stain… exactly like the one behind Mr. DuBois' chair!” His finger waggled accusingly, all eyes turned to me, and I looked behind my chair to find that it was indeed as he said. I must have spilled some of the nitrogen triiodide there the previous day while surreptitiously showing it off to my classmates. He didn't pursue the matter, but did make class difficult for me from then on. I felt better about it when I imagined him with his little brush and dustpan, reaching down to gather up the evidence so very carefully. The brush touches the now-dry “iodine”…

I did at long last find something useful to do with the material, for sufficiently small values of “useful”. Another of those who had seen the demonstrations was my friend Alec. He and I were continually getting into arguments over every object under the sun, and for that matter inside it (“Is the inside of the sun hotter than the outside?”). These arguments generally devolved into facetious threats. His latest threat was that he would pour herbicide upon my cacti. I responded by assuring him that one day I would push some nitrogen triiodide into the crack between his school locker and its door. He replied that he would simply kick the door before opening it. He did, too. For several days after various classes I went down to the wing his locker was on, and watched as he stood to the side and reached his leg around to kick it. Other people also watched, presumably interpreting it as some sort of bizarre ritual, which in a sense it was. I finally carried out my threat on the last day of school. When I went down during break to see what would happen, I found that I was too late; his locker was open. I wondered whether he had remembered to kick it. When I saw the expression on his face, I decided that he hadn't.

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