General Description
An odorless white crystalline powder. Insoluble in water and denser than water. Hence sinks in water. Very toxic by inhalation and ingestion.
Reactivity Profile
MERCURY THIOCYANATE(592-85-8) decomposes into its elements at about 165°C. Burns readily in air to generate a coil of cohesive ash resembling a serpent (hence used in a firework: Pharaoh's serpents). Swells up to many times its original volume if heated [USCG, 1999]. Soluble in dilute hydrochloric acid [Merck]. Incompatible with strong oxidizing agents.
Air & Water Reactions
Insoluble in water.
Hazard
Highly toxic by ingestion, inhalation, and
skin absorption.
Health Hazard
INHALATION: Acute poisoning symptoms are: Tightness in the chest, difficulty in breathing, coughing, and pain in the chest. EYES: Ulceration of conjunctiva and cornea. SKIN: Irritation, sensitization dermatitis. INGESTION: Necrosis, pain, vomiting, severe purging. Patient may die within a few hours from peripheral vascular collapse.
Potential Exposure
Mercury thiocyanate is used in
photography and fireworks.
First aid
If this chemical gets into the eyes, remove any
contact lenses at once and irrigate immediately for at least
15 minutes, occasionally lifting upper and lower lids. Seek
medical attention immediately. If this chemical contacts the
skin, remove contaminated clothing and wash immediately
with soap and water. Seek medical attention immediately.
If this chemical has been inhaled, remove from exposure,
begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR if
heart action has stopped. Transfer promptly to a medical
facility. When this chemical has been swallowed, get medical attention. Give large quantities of water and induce
vomiting. Do not make an unconscious person vomit.
Antidotes and Special Procedures for medical personnel:
The drug NAP has been used to treat mercury poisoning,
with mixed succes
Shipping
UN1646 Mercury thiocyanate, Hazard Class:
6.1; Labels: 6.1-Poisonous materials.
Incompatibilities
Incompatible with oxidizers (chlorates,
nitrates, peroxides, permanganates, perchlorates, chlorine,
bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases,
strong acids, oxoacids, epoxides. Mercury thiocyanate is
sensitive to heat; expands to many times its original volume
and then decomposes at freezing/melting point forming
toxic fumes of sulfur oxides, mercury cyanide, and nitrogen
oxides. Contact with acid or acid fumes causes release
of toxic mercury and cyanide vapors. Incompatible with
chlorine, reducing agents such as hydrides, sulfides
Description
Mercury thiocyanate is a white, odorless powder. Molecular weight= 316.79; Freezing/Melting point=about 165℃ (decomposes). Slightly soluble in cold water.
Chemical Properties
Mercuric thiocyanate is an inorganic chemical substance. It is a stable solid at room temperature, and depending upon the purity, it appears as odourless white crystalline powder or grey. It is insoluble in water and denser than water and sinks in water. On decomposition, mercuric thiocyanate releases hazardous substances such as cyanide vapours, vapours of mercury, oxides of nitrogen (NO, NO2), and oxides of sulphur (SO2, SO3). Mercury thiocyanate has limited uses in chemical synthesis.
Chemical Properties
Mercury thiocyanate is a white, odorless
powder.
Waste Disposal
Small amounts may be
destroyed by alkaline hydrolysis. Admixture with alkali
can be followed by soil burial. Larger quantities can be
disposed of by incineration in admixture with acetone or
xylene and using effluent gas scrubbing. Do not reuse
empty container; proper disposal required.
Uses
For Pharaoh's serpents (fireworks); intensifier in photography.
Uses
Mercury(II) thiocyanate is used as a precursor to potassium tris(thiocyanato)mercurate(II) and cesium tris(thiocyanato)mercurate(II). It is also used in the determination of chloride ions in water by UV-visible spectroscopy. Further, it acts as a catalyst for the addition of thiocyanic acid to alkynes.
Synthesis
A Hg(NO3)2
solution, acidified with a few drops of HNO3,
is treated with the stoichiometric amount of KSCN solution. The
resultant crystalline precipitate is suction-filtered and washed
with H2O. The product may be recrystallized from hot H2O or
alcohol. Yield 80%.
Hg(NO3)2 + 2 KSCN = Hg(SCN)2 + 2KNO3
storage
Color Code—Blue: Health Hazard/Poison: Store in a secure poison location. Prior to working with this chemical you should be trained on its proper handling and storage. Store in tightly closed containers in a cool, wellventilated area away from light, heat, and acids, including fumes.
Purification Methods
Recrystallise it from H2O, and it can give various crystal forms depending on conditions. Its solubility in H2O is 0.069% at 25o, but is more soluble at higher temperatures. It decomposes to Hg above 165o. Poisonous. [Mason & Forgeng J Phys Chem 35 1121 1931, Birckenbach & Kolb Chem Ber 68 919 1935.]
