Preparation of Silver Tetraiodomercurate(II) for a demonstration.

Silver Tetraiodomercurate(II) is a quite special compound, since it’s thermochromic. It changes color from yellow to orange/red when heated: http://labphoto.tumblr.com/post/111304710632/yesterday-i-posted-about-fluorescence

Silver Tetraiodomercurate (Ag2HgI4) is yellow at room temperature, but when it’s heated above 50 °C, it turns orange. Since the color change is reversible, when it is cooled back to room temperature, the color changes back to its original color.

The compound was prepared from mercury(II)-iodide (that red powder on the first picture) and some potassium iodide with a little silver nitrate. The silver nitrate was added to the solution of potassium tetraiodomercurate (K2HgI4,   what was previously prepared from mercury-iodide and potassium iodide). The addition of the silver salt caused the immediate precipitation of the yellow colored silver tetraiodomercurate (as seen on the gif).

What happened? This:

HgI2 + 2 KI + 2 AgNO3 –> Ag2HgI4 + 2 KNO3

Chibi Vulpixes :D I want to try to make some wooden charms, and thought I’d try something else here, using my Pokémon variation designs. Would you be interested in such thing? What other designs would you like as a charm? 

Who was the oldest fighter at the #EJCVeterans?
It was Vuk Rasovic from Serbia. The 76 years old judoka won two of his three fights. Now he is pleased about his silver medal at the #EJCVeterans.

“I start Judo in 1960 and I participated in three European Championships. And until now I never stopped with Judo. I think I am maniac and maybe one day I will die on the tatami.”

Source: EJU