Lithium tungstate

Lithium tungstate

Identifiers
CAS Number	13568-45-1
ECHA InfoCard	100.033.602
Properties
Chemical formula	Li2O4W
Appearance	white solid
Density	4.56 g/cm3
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Lithium tungstate is the inorganic compound with the formula Li₂WO₄. It is a white solid that is soluble in water. The compound is one of the several orthotungstates, compounds that feature the tetrahedral WO₄^2- anion.

Structure

The salt consists of tetrahedrally coordinated Li and W centres bridged by oxides. The W-O and Li-O bond distances are 1.79 and 1.96 Å, respectively. These differing bond lengths reflect the multiple bond character of the W-O interaction and the weaker ionic bonding between the Li-O interactions. The solid undergoes phase transitions at high pressures, such that the coordination geometry at tungsten becomes octahedral (six W-O bonds). For example at 40 kilobars, it adopts a structure related to wolframite.

Uses

Lithium tungstate is used to produce high density water solutions. Like other high density fluids, it is often used in the separation of minerals and other solids.

This use was developed in the early 1990s to address issues with existing high density fluids such as toxicity, safety, and stability, Unlike methylene iodide and bromoform it can safely be used in an indoor environment without a fume hood with only ordinary common sense safety precautions such as protective gloves and safety glasses.