"Fuzzy" Applets The following is a supplement to the article "Using Fuzzy Logic for Molecular Modeling" by David A. Ress, which is as part of JOM-e, 51 (8) (1999).

This page presents two Java applets:

• One for calculating fuzzy bond lengths and fuzzy bond angles for chalcopyrite compounds (other that the CuInSe₂ example provided in the main paper).
• One for calculating the fuzzy density of a chalcopyrite compound.

Fuzzy Chalcopyrites	Fuzzy Density
As chalcopyrites are ABC2 compounds and this example analyzes the bond lengths and bond angles around a single tetrahedron from the unit cell, the following figure provides insight into the understand the values calculated by the applet. For example, if you choose CuFeS2, then the bond length c1_a1 represents the distance from sulfur to copper1 and so forth.	Density is the relationship of mass divided by volume. To calculate the volume, we use the lattice parameters and convert the answer into cubic centimeters. As we have fuzzy lattice parameters, the volume of the unit cell is fuzzy as well. The mass of the unit cell is found by using the amu value for each compound times the number of times each compound occurs in the unit cell. Then, the total mass is divided by the fuzzy volume, which provides a fuzzy density value.