Revisiting Chalcogenides

Today I came across an article detailing how Intel and STMicroelectronics are teaming up to produce flash memory with significantly faster speeds. They are utilizing a PCM (phase change material) which alternates between liquid and crystalline states using the application of electric pulses. The sentence which caught my eye was “PCM memory uses a chalcogenide gas that is kept in one of two states, liquid or crystalline.” Besides the fact that I’m pretty sure they meant to say “glass” instead of “gas,” I am slightly embarrassed to admit that I was no longer sure which elements could be described as “chalcogens.” Since I have never used or studied Se, Te, or Po at any time in my life, I suppose that I shouldn’t feel too bad about not recalling the term from graduate school. (I’ve used O and S extensively, but frankly, no one really calls them chalcogens unless Se or Te is a part of the conversation). However, one of the guys I shared a house with in graduate school (his name was Gregg) did work extensively with S and Se and it was from him that I learned the definition of chalcogenides. In addition, his advisor, Tom Rauchfuss, graciously allowed me to complete my PhD work in his group’s lab space when my lab space was taken over by another professor. I was literally surrounded by chalcogens for a 2 year period and yet I managed to forget them after spending time in the “real world.” I would like to humbly apologize to both Gregg and Tom.

Btw, while looking up the term “chalcogenide” I was surprised to see that the “ch” is pronounced like a “k”. Perhaps my memory is failing me, but I’m fairly sure that I’ve always heard it pronounced like the “ch” in “chalice.”