Hazard
Toxic by ingestion.
Chemical Properties
Magnesium is an essential nutrient for plants and animals and is
a natural constituent of fruits, vegetables, grain, meats and sea-foods. It is the fourth most abundant cation in the human body
and the second most plentiful intracellularly. The average 60-kg
human adult body contains about 24 g magnesium of which about
one-half resides in bone. Although plasma levels vary between 1.7
and 3.0 mg per dl, very little is contained in extracellular fluid.
Magnesium is essential for the production and transfer of energy,
for protein, fat, and nucleic acid synthesis, for contractility in
muscle and excitability in nerve, and for the activity of numerous
enzyme systems.
Occurrence
MgCl2, is one of the primary constituents of seawater and occurs in most natural brines and salt deposits formed from the evaporation of seawater.
Definition
ChEBI: Magnesium chloride is a magnesium salt comprising of two chlorine atoms bound to a magnesium atom.
Definition
magnesium chloride: A white solid compound, MgCl2. The anhydrous salt (hexagonal; r.d. 2.32; m.p.714°C; b.p. 1412°C) can be prepared by the direct combination of dry chlorine with magnesium:
Mg(s) + Cl2(g) → MgCl2(s)
The compound also occurs naturally as a constituent of carnallite(KCl.MgCl2). It is a deliquescent compound that commonly forms the hexahydrate, MgCl2.6H2O (monoclinic;r.d. 1.57). When heated, this hydrolyses to give magnesium oxide and hydrogen chloride gas. The fused chloride is electrolysed to produce magnesium and it is also used for fireproofing wood, in magnesia cements and artificial leather, and as a laxative.
Preparation
In the “Dow Process” (which is the electrolytic
method of extracting bromine from brine), magnesium
chloride is regenerated from magnesium hydroxide by
hydrochloric acid:
Mg(OH)2(s)＋2HCl→MgCl2(aq)＋2H2O
It can also be prepared from MgCO3 by a similar reaction.
Magnesium chloride is ionic and so will undergo
electrolysis when it is molten. Electricity is carried by
the movement of the ions within the melt and their
discharge at the electrodes. However, solid magnesium
chloride is a nonconductor of electricity because the
ions are immobile.
Flammability and Explosibility
Nonflammable
Toxics Screening Level
The initial threshold screening level (ITSL) for magnesium chloride is 5 μg/m3 based on an annual averaging time.
