Fluorescence thermochromism of pyridine-copper-iodide complex. At room temperature it has a yellow emission, but when it is cooled with liquid nitrogen to low temperatures (-195 °C) the fluorescent color changes to blue/purple. When the ampule is removed from the nitrogen and warms up, the color changes back.

On the gifs I placed an ampule in a transparent Dewar flask with some liquid nitrogen inside it. Between the walls of the glass there is vacuum what acts as a thermal insulator and prevents the liquid nitrogen from fast evaporation.

9:30 pm • 19 February 2015 • 637 notes • View comments