While browsing my archives, I stumbled across a screencast demonstrating ChemTrix for iPad that I made over three years ago. I am embarrassed to admit that I have not updated this app since June 3rd, 2013. Though it was designed against iOS 6, it still works perfectly on my 13" iPad Pro running iOS 10. This is much more a testament to Apple's support of legacy software than it is to my own forward thinking. I say "um" frequently in this video. How I wish that were not the case.
iOS