Atomic Positional Parameters
Ca 4b  0.0000 0.2500 0.6250
O  16f 0.1504 0.0085 0.2111
W  4a  0.0000 0.2500 0.1250

Chime crystal offset by
(0.0000, -0.2500, -0.1250)

Reference
A Zalkin and DH Templeton (1964) J. Chemical Physics, 40, 501

Mineral Chemistry
Scheelite is named after the 18th century Swedish chemist Scheele, who discovered tungsten. A high temperature mineral and important ore of tungsten, scheelite is found in quartz veins and pegmatites. Associated minerals include wolframite, cassiterite, molybdenite, arsenopyrite, chalcopyrite, apatite, tourmaline, topaz, mica and fluorite.

Scheelite has a body-centred unit cell. Tungstate (WO₄) tetrahedra are compressed perpendicular to the c-axis, and calciums are coordinated by eight oxygens. Powellite (CaMO₄), stolzite (PbWO₄) and wulfenite (PbMoO₄) are members of the scheelite group of minerals, and synthetic phases NaIO₄, KIO₄, BaMoO₄ and BaWO₄ also crystallise with this structure.

The CHIME figure shows calcium ions as large grey spheres, oxygens as red spheres, and tungstens as crimson spheres. The unit cell is outlined.