Editing Torbernite (section)

== Crystal structure ==
[[Image:Torbernite - packing.png|thumb|left|Packing of torbernite. Colour code: <span style="color: green">[[uranium]]</span>, <span style="color: lime">[[copper]]</span>, <span style="color: yellow">[[phosphorus]]</span>, <span style="color: red">[[oxygen]]</span>, <span style="color: grey">[[water]]</span>, <span style="color: silver">[[hydrogen]]</span>]]

Torbernite crystallises in the tetragonal [[space group]] ''I''4/''mmm'' with the lattice parameters ''a''&nbsp;=&nbsp;7.0267(4)&nbsp;Å und ''c''&nbsp;=&nbsp;20.807(2)&nbsp;Å and 2 formula units per unit cell.<ref name="LocockBurns" />

In a study in 2003, using fresh, synthetic crystals, Locock and Burns have compared the crystal structures of the copper uranyl phosphates torbernite, Cu[(UO<sub>2</sub>)(PO<sub>4</sub>)]<sub>2</sub>(H<sub>2</sub>O)<sub>12</sub> and metatorbernite, Cu[(UO<sub>2</sub>)(PO<sub>4</sub>)]<sub>2</sub>(H<sub>2</sub>O)<sub>8</sub> with those of the copper uranyl [[arsenate]]s zeunerite, Cu[(UO<sub>2</sub>)(AsO<sub>4</sub>)]<sub>2</sub>(H<sub>2</sub>O)<sub>12</sub>, and metazeunerite, Cu[(UO<sub>2</sub>)(AsO<sub>4</sub>)]<sub>2</sub>(H<sub>2</sub>O)<sub>8</sub>. In these studies they were able to finally analyse the crystal structure of torbernite for the very first time, and to get a significantly more precise analysis for the structure of metatorbernite, compared with previous studies (Makarov and Tobelko [[R-factor (crystallography)|''R''1]] = 25%,<ref name="Makarov" /> Ross et al. ''R''1 = 9.7%,<ref name="Ross" /> Stergiou et al. ''R''1 = 5.6%,<ref name="Stergiou" /> Calos and Kennard ''R''1 = 9.2%<ref name="Calos" /> vs. Locock und Burns ''R''1 = 2.3%).

The study shows that torbernite is [[isostructural]] to zeunerite, and metatorbernite is isostructural to metazeunerite. All four compounds are of the layered autunite type with the [(UO<sub>2</sub>)(XO<sub>4</sub>)]<sup>−</sup> structural motif (with X = P or As). The Cu<sup>2+</sup> ions are coordinated in a square-planar fashion by water molecules in all these compounds, and further coordinate to the uranyl oxygen atoms, forming octahedra with [[Jahn–Teller effect|Jahn-Teller distortion]]. The additional water molecules are held in the crystal structure only by [[Hydrogen bond|hydrogen bridges]].