One of the chemical compounds that has created the most controversy in recent years is silver iodide. It is an inorganic compound that is made up of a silver atom and an iodine atom. It is a light-colored yellow crystalline solid that tends to darken when exposed to light for a long time. It is not soluble in water but can dissolve in the presence of a high concentration of iodide ion.
In this article we are going to tell you about all the characteristics, properties and uses of silver iodide.
Key features
We are talking about an inorganic compound that contains a crystalline structure similar to that of ice. Over the years, the experience with this compound has matured and it has been given numerous uses. One of them is to serve as a seed to produce rain and change the climate. This use has been widely questioned due to the potential damage silver iodide can cause when dissolved in water. Furthermore, there are no known long-term effects that modifying the climate of a region can have.
Since the nineteenth century it has been used in photography thanks to the ability to darken with light. It is also used in antimicrobial therapies. Recently there are some studies on the use of silver iodide in the removal of radioactive iodine in the waste produced in nuclear power plants.
It is a compound that it is toxic to humans, animals and plants. Therefore, there is great controversy about the use of silver iodide for modifying the climate and generating rain. The structure of this compound is formed by its oxidation state of silver and iodine with valence -1. The bond between the two ions is very strong and stable. This is one of the reasons that it is hardly insoluble in water. The crystalline structure depends on the temperature in which we are. Below 137 degrees there is a cubic shape, between 137 and 145 degrees we have a solid with a greenish-yellow or beta-shaped color. Lastly, if the temperature rises above 145 degrees, it will present silver iodide with a yellow color and in its alpha form.
Silver Iodide Properties
We know that in its natural physical state it is a solid with a light yellow color that forms hexagonal or cubic crystals. Its molecular weight is 234.773 grams for each mole and its melting point is 558 degrees. In order for Heliodorus to boil silver it must reach temperatures of 1506 degrees.
As we have mentioned before, it is an inorganic compound practically soluble in water. It is insoluble in acids except hydroiodic acid and is soluble in concentrated solutions such as alkali bromides and alkali chlorides. Among its chemical properties we have acids that are concentrated as long as they are high temperatures and attack slowly. Solutions in which there is an excess of the iodide ion are dissolved, forming a complex of iodine and silver. One of the properties for which it stands out is that it is sensitive to light. If the light is exposed for a long time, it slowly darkens and forms metallic silver.
Silver iodide uses
This compound is obtained in nature in the form of the mineral iodargyrite. Once it is in the laboratory, it can be prepared by heating the silver nitrate solution with an alkaline iodide solution such as potassium iodide. In this way, the silver iodide is artificially created.
One of the most controversial uses of silver iodide throughout history is to generate rain. I know You can apply in clouds to change the amount or type of precipitation. It can trigger hail processes, disperse cold fogs or weaken hurricanes. To do this, it can be dispersed as if it were a seed within a cold cloud that contains supercooled liquid water. Eta means that the temperatures are below 0 degrees. By having a crystalline structure similar to that of ice, it favors the freezing of supercooled water.
The problem of the use of silver iodide for the generation of rain is its adverse effects. And it is that after dispersion as a seed in the clouds it is found inside it and is washed away by precipitation. The presence of a soluble silver hard in rainwater is something that must be taken into account since it is polluting and toxic to plants, animals and humans. The marine environment also affects all animals and plants.
Cloud seeding is an experiment that was conducted a few decades ago. If clouds are planted respectively over the same area, can create a cumulative silver iodide effect. According to several recent studies, the concentration of silver iodide found in areas where the cloud seeding technique has been used is much higher than the limit from which it is toxic to some fish and lower organisms.
It can be said that the only rational use of silver iodide would be to weaken hurricanes, thus reducing their consequences.
Other uses
As we mentioned before, due to the sensitivity of light it was used in photography. It is a material capable of reacting in the presence of light. This means that it is used in obtaining photosensitive materials such as photographic rolls on which the crystals were applied. Thanks to silver iodide we were able to take photos from an old camera.
Another use is in the removal of radioactive iodine. As it has high insolubility, it has been proposed to remove the radioactive iodine found in the aqueous waste generated in nuclear power plants.
I hope that with this information you can learn more about silver iodide and its uses.
