Heavy liquid


A heavy liquid is a solution or liquid chemical substance with a high density and a relatively low viscosity. Heavy liquids are often used for determination of density in mineralogy, for density gradient centrifugation and for separating mixtures.

Uses

Common applications of heavy liquids include:
The classical heavy liquids like 1,1,2,2-tetrabromoethane, potassium tetraiodomercurate, bromoform or diiodomethane which are used in mineralogy are very toxic. These toxic chemicals are avoided today in consideration of the fact that there are alternative water based, non-toxic heavy liquids like sodium polytungstate solutions. With this relatively new heavy liquid densities up to 3.1 g·cm−3 can be adjusted. Adding parts of pulverulent Tungsten carbide increases the density to 4.6 g·cm−3.

List of common heavy liquids with density > 2.0 g·cm−3

NameDensity in g·cm−3
1,2-Dibromoethane2.180
cis-1,2-Dibromoethene2.246
trans-1,2-Dibromoethene2.231
Dibromomethane2.477
Bromal2.550
Bromoform2.890
1,1,2,2-Tetrabromoethane 2.967
Sodium polytungstate3.100
Bromine3.1028
Thoulets solution3.196
Diiodomethane3.325
Indiumiodide3.40
Bariummercuriciodide3.57
Thallium formate + Thallium malonate 4.25
Liquid metal 6.5
Mercury13.6

Literature