Ammonium thiosulfate

  • Ammonium hyposulfite
  • Thiosulfuric acid, diammonium salt
Formula
(NH4)2(S2O3)
Structure
Description
Ammonium thiosulfate is a white crystalline solid.
Uses
To clean white metal, in photography, in lubricants for metal cold-working.

Registry Numbers and Inventories.
CAS
7783-18-8
EC (EINECS/ELINCS)
231-982-0
R 36/37/38
RTECS
XN6465000
RTECS class
Other
Merck
13,565
Beilstein/Gmelin
44264 (G)
EPA OPP
80103
Canada DSL/NDSL
DSL
US TSCA
Listed
Austrailia AICS
Listed
New Zealand
Listed
Japan ENCS (MITI)
Listed
Korea ECL
Listed

Properties.
Formula
H8N2O3S2
Formula mass
148.19
Vapor density (air=1)
<1
Density
1.67 g/cm3
Solubility in water
Soluble

Hazards and Protection.
Storage
Keep containers tightly closed in a well ventilated area away from food products. Keep away from heat and water and store at temperatures above 20 C.
Handling
All chemicals should be considered hazardous. Avoid direct physical contact. Use appropriate, approved safety equipment. Untrained individuals should not handle this chemical or its container. Handling should occur in a chemical fume hood.
Protection
Respirator; rubber gloves; safety glasses; face shield; rubber apron, shield, or suit as necessary to prevent skin contact.
Respirators
Use NIOSH/MSHA approved respirator appropriate for exposure of concern.
Small spills/leaks
Keep material out of water sources and sewers. Build dikes to contain flow as necessary. Land spill: Dig a pit, pond, lagoon, holding area to contain liquid or solid material. Cover solids with a plastic sheet to prevent dissolving in rain or fire fighting water. Water spill: Neutralize with dilute acid. If dissolved, in region of 10 ppm or greater concentration, apply activated carbon at ten times the spilled amount. Use mechanical dredges or lifts to remove immobilized masses of pollutants and precipitates.
Stability
Solutions decompose slowly below 50 C and more rapidly at higher temperatures. The anhydrous salt decomposes above 100 C to sulfite and sulfur.
Incompatibilities
Sensitive to heat Incompatible with magnesium and aluminum powder Mixtures with sodium chlorate can cause an exothermic reaction which can then decompose explosively Reacts with strong oxidizers such as chlorates, nitrates, and nitrites to release toxic ammonia, hydrogen sulfide, and sulfur trioxide gases.
Decomposition
Decomposed by heat.

Fire.
Fire fighting
Extinguish fire using agent suitable for type of surrounding fire. (Material itself does not burn or burns with difficulty.)
Fire potential
Nonflammable.
Combustion products
Toxic ammonia, hydrogen sulfide, and oxides of nitrogen and sulfur may form in fires.

Health.
Exposure effects
   Ingestion
Ingestion of large doses may result in gastroenteritis and a cathartic action.
   Inhalation
Inhalation of dust may irritate respiratory system. Ingestion could be harmful. Contact with eyes or skin may cause irritation.
   Skin
See inhalation.
   Eyes
See inhalation

First aid
 
   Ingestion
DO NOT INDUCE VOMITING. If the victim is conscious and not convulsing, give 1 or 2 glasses of water to dilute the chemical and IMMEDIATELY call a hospital or poison control center. Be prepared to transport the victim to a hospital if advised by a physician.
   Inhalation
IMMEDIATELY leave the contaminated area; take deep breaths of fresh air. If symptoms (such as wheezing, coughing, shortness of breath, or burning in the mouth, throat, or chest) develop, call a physician and be prepared to transport the victim to a hospital. Provide proper respiratory protection to rescuers entering an unknown atmosphere. Whenever possible, Self-Contained Breathing Apparatus (SCBA) should be used.
   Skin
IMMEDIATELY flood affected skin with water while removing and isolating all contaminated clothing. Gently wash all affected skin areas thoroughly with soap and water. If symptoms such as redness or irritation develop, IMMEDIATELY call a physician and be prepared to transport the victim to a hospital for treatment.
   Eyes
First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop.

Transport.
USCG CHRIS Code
ATV
 
43 Misc. water solutions
Std. Transport #
4966753
 
IMO Chemical Code
17
IMO Pollution Category
C
IMO Hazard code
P