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Diss Factsheets
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EC number: 231-867-5 | CAS number: 7772-98-7
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
Melting point / freezing point
Administrative data
Link to relevant study record(s)
- Endpoint:
- melting point/freezing point
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 2010-06-16
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 102 (Melting point / Melting Range)
- Deviations:
- no
- Qualifier:
- according to guideline
- Guideline:
- EU Method A.1 (Melting / Freezing Temperature)
- Deviations:
- no
- Qualifier:
- according to guideline
- Guideline:
- other: OECD 113 (1981) Screening test for thermal stability and stability in air
- Deviations:
- no
- GLP compliance:
- yes (incl. QA statement)
- Remarks:
- signed, 2009-10-29
- Type of method:
- other: differential scanning calorimetry (DSC)
- Decomposition:
- yes
- Decomp. temp.:
- <= 500 °C
- Remarks on result:
- other: The test item decomposes during the measurement up to 500°C
- Conclusions:
- Sodium thiosulfate shows no melting in the temperature range of 25-500 °C. The observed endothermic effects are presumably assigned to decomposition (disproportionation) or effects like phase transitions.
- Endpoint:
- melting point/freezing point
- Type of information:
- other: Handbook data
- Adequacy of study:
- supporting study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- data from handbook or collection of data
- Remarks:
- From a trusted source acc. to "ECHA, Guidance on information requirements and chemical safety assessment – Chapter R.7a: Endpoint specific guidance"
- Qualifier:
- no guideline followed
- Principles of method if other than guideline:
- Not applicable - Handbook data
- GLP compliance:
- not specified
- Type of method:
- other: no data
- Decomposition:
- yes
- Decomp. temp.:
- 100 °C
- Conclusions:
- According to the reference, sodium thiosulphate decomposes at 100 °C.
Referenceopen allclose all
A DSC-measurement in closed glass crucibles showed two endothermic peaks in the temperature range 320 -345 °C and 380 -395 °C, respectively. No further effects were observed up to the maximum temperature.
The measurement in an aluminium crucible with a hole showed two endothermic effects in the temperature range 320 to 365 °C and 380 to 405 °C. In the temperature range 425 to 500 °C an exothermic effect with energy of 236 J/g has been observed. An optical inspection after the measurement showed that the test item was still a solid. The test item was discoloured to yellow.
Description of key information
Sodium thiosulfate has no melting in the temperature range of 25 - 500 °C. The test item decomposes during the measurement up to 500 °C.
Key value for chemical safety assessment
Additional information
For the evaluation of this endpoint data from an experimental study were used as key information, supported by data from the CRC handbook. The study was conducted according to GLP and according to OECD guidelines 113 (screening for thermal stability) and 102 (determination of melting point). The test data are considered as reliable without restrictions.
The thermal stability and the determination of the melting point were carried out by DSC analysis. The test item and the standard material (aluminium oxide) were heated up from ambient temperature to the final temperature (400°C and 500°C, respectively.) at a constant heating rate under nitrogen. Closed class crucibles were used as containers for the screening test and aluminium crucibles with a small hole were used as containers for the main test. The quantity of heat absorbed or released was measured and recorded.
Experimental study results indicated that sodium thiosulfate has no melting point in the temperature range of 25 -500 °C. The test item decomposes during the measurement up to 500°C.
The decomposition is confirmed by the information obtained from the CRC Handbook of Chemistry and Physics. However, according to handbook data, sodium thiosulfate decomposes at 100 °C.
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