You've seen this in the news before: We are running out of resources. Oil (a perennial favorite), indium (for many years now), or (as of November 2014), chocolate. Name your resource and you can find somebody that will tell you it'll be gone soon.
With indium, every couple of months we see another article that claims we are just short of running out it altogether. Don't believe a word of it.
This is a large topic, and in a way it is like the Hydra of Greek mythology. You know, the monster that Hercules had to slay as part of his to-do list. Hydra started out with three heads, and every time Hercules cut one head off it grew two more.
(Mathematical side note: If the number of heads isn, afterkhits you are left withn = (k+3)heads. This is linear growth. The incidence of indium resource stories seems to me more like an exponential curve.)
So let's start withallthe elements:
There are 98 elements from the periodic table that occur in nature. Line them up by atomic number and the element indium is right in the center, at atomic number 49.
Below is a great chart, published by the USGSthat shows the abundance of the elements on earth:
Notice the logarithmic scale on the y-axis. Each major tick mark denotes an entire decade. Notice the rock-forming elements in the green area. The group of rarest elements, highlighted in yellow includes Ruthenium, Rhodium, Palladium, Tellurium, as well as Gold (Au) and Platinum. Rarest element of the all? Iridium.
Where's Indium? About two decades, i.e. 100 times more abundant than gold or platinum.
Also note Indium is pretty much level with silver (Ag) and mercury (Hg), both elements that are very familiar. Think jewellery, old-fashioned cutlery and photographic film (for silver), and old-fashioned thermometers, ceiling, and street lamps (for mercury). Indium, in turn, supports such new-fashioned technologies as LCDs, the touchscreen on your device and a myriad of semiconductor applications.
So why is there no discussion on the rarity of silver and mercury? Could it be that we are using way more indium than those metals? Is demand growing very fast, and we are running out of a fixed supply? I'll be answering these questions in my next post, so stay tuned! In the meantime, if you are looking to buy some indium — please see ourproduct pages, and if you are interested in indium metal start here).
