Abstract 2-Dimethylsulfuranylidene-l. 3-indanedione (YLID) is the most common crystal structure in the world not because of its chemical or physical properties. but because of its use as a test crystal for commercial diffractometers by nearly all vendors for more than 50 years. We will use it as an example here to showcase how the application of modern quantum-crystallographic refinem... https://parisnaturalfoodes.shop/product-category/absolute-iron/