Atomic Positional Parameters
O  4a 0.0000 0.0000 0.0000
O  4e 0.5000 0.1163 0.7500
O  8f 0.2660 0.1234 0.9401
O  8f 0.3114 0.1038 0.3282
O  8f 0.0172 0.2117 0.4782

Si 8f 0.1403 0.1083 0.0723
Si 8f 0.5068 0.1580 0.5408

Reference
Levien and Prewitt (1981) American Mineralogist 66 324-333.

Mineral Chemistry
Coesite is the high-pressure, high-temperature polymorph of silica. It is named after Loring Coes Jr., who discovered this phase in experimental studies in 1953. The conditions of formation are 500-800^oC and ~30-35 kbar. This mineral is found in impact craters and crustal eclogite facies, where it has been formed under high pressure and high temperature conditions. The structure is composed of four-tetrahedron rings linked into a three-dimensional framework.

The CHIME figure shows silicon as yellow spheres, and oxygens as red spheres.