Dear Faldage: amazing what can be found on Internet! I searched for "NI3" and got
a ten year old post by a guy who as a High School freshman made iodine from an old
chemistry book experiment adding KI to sulfuric acide. It gave off gaseous iodine, which
he collected on an ice filled Petri ;dish. That would be reversed sublimation. He then
made NI3, in an aluminum dish. It ate through the dish onto floor. He says he got a
surprise when he went into his (fortunately) isolated chemistry shack the next day.
I'll bet he did.