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
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
Indium iodide3.40
Barium tetraiodomercurate3.57
Thallium formate + thallium malonate 4.25
Galinstan 6.44
Mercury13.6

Mercury is the heaviest liquid at room temperature. But the heaviest liquid irrespective of temperature is liquid osmium at its melting point, with a density of 22.59 g·cm−3, 1.65 times as heavy as mercury.

Literature

  • Schnitzer W, Zur Problematik der Schwermineralanalyse am Beispiel triassischer Sedimentgesteine, in International Journal of Earth Sciences, 72/1983, S.67–75, ISSN 1437-3254 1437-3262
  • Boenigk, Schwermineralanalyse, S.6–15, Stuttgart: Enke, 1983.
  • Ney, Gesteinsaufbereitung im Labor, S.92–113, Stuttgart: Enke, 1986.