Baddeleyite

Baddeleyite [ZrO₂]

Structure Monoclinic
Space Group : P2₁/c (No. 14)
a=5.1450 Å, b=5.2075 Å, c=5.3107 Å
a=90.00, b=99.23, g=90.00
Z=4

Atomic Positional Parameters
Zr 4e 0.2758 0.0411 0.2082
O1 4e 0.0703 0.3359 0.3406
O2 4e 0.4423 0.7549 0.4789

Reference
Smith DK, and Newkirk HW (1965) Acta Crystallographica, 18, 963

Mineral Chemistry
Baddeleyite, a rare mineral, may be found in syenites and carbonatites, and as a detrital mineral in gem gravels. Baddeleyite may contain hafnium in concentrations varying from 0.1 to several percent.

In baddeleyite, zirconiums are in seven-fold coordination with oxygen. Two types of oxygen coordination exist - one type of oxygen is at the centre of a triangle of three zirconiums, the other is at the centre of a distorted tetrahedron of zirconiums.

The Chime figure shows oxygens as red spheres and zirconiums as magenta spheres