The chloride ion is formed when the
element chlorine picks up one electron to form an anion (negatively-charged
ion) Cl-. The salts of hydrochloric acid HCl contain chloride ions and can
also be called chlorides. An example is table salt, which is sodium chloride
with the chemical formula NaCl. In water, it dissolves into Na+ and Cl-
ions.
The word chloride can also refer to a chemical compound in which one or
more chlorine atoms are covalently bonded in the molecule. This means that
chlorides can be either inorganic or organic compounds. The simplest example
of an inorganic covalently-bonded chloride is hydrogen chloride, HCl.
Keep
in a tightly closed container, stored in a cool, dry, ventilated area.
Protect against physical damage. Isolate from incompatible substances.
Containers of this material may be hazardous when empty since they
retain product residues (dust, solids); observe all warnings and
precautions listed for the product. 
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Ingestion:
Since magnesium salts are slowly absorbed, abdominal pain, vomiting and
diarrhea may be the only symptoms. However, if elimination is blocked by
bowel blockage or other reasons, CNS depression, lack of reflexes,
hypocalcemia (deficiency of calcium in the blood) may occur. 