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EC number: 215-170-3 | CAS number: 1309-42-8
- 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:
- 19-03-2010 to 15-06-2010
- 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
- GLP compliance:
- yes (incl. QA statement)
- Type of method:
- differential scanning calorimetry
- Specific details on test material used for the study:
- - Name: Magnesium hydroxide
- Batch no. 20BR0026
- CAS No.: 1309-42-8
- Purity: 99.9 %
- Expiry date: 31 January 2012
- Storage Room Temp. in the dark - Key result
- Decomposition:
- yes
- Remarks:
- An exothermic point was observed at > 320°C - no visual changes observed in comparison to original test substance.
- Decomp. temp.:
- > 320 °C
- Conclusions:
- Reaction and/or decomposition of the test substance was observed at temperatures of > 320 °C (> 593 K).
An exothermic point was observed at 375.05°C (extrapolated from onset temperature 344.81) - no visual changes observed in comparison to original test substance.
Melting of the test substance was not observed below the temperature at which reaction/decomposition started.
Therefore the test substance has no melting point. - Executive summary:
In a GLP guideline study according to OECD 102 and EEC A.1, the melting point of Magnesium hydroxide was investigated.
The melting point of Magnesium hydroxide was determined using DSC. Reaction and/or decomposition of the test substance was observed at temperatures of > 320 °C (> 593 K). Melting of the test substance was not observed below the temperature at which reaction and/or decomposition started.
Based on this, the test substance has no melting point.
Reference
Preliminary test:
6.15 mg of test substance was heated at a rate of 20 °C/minute from 25 °C to 550 °C. At this point 28 % weight loss of the test substance was observed. After the experiment the sample was cooled to 50 °C and the consistency of the test substance was determined.
Main study:
After each of the experiments, no visual changes could be observed when compared to the original test substance.
In the first experiment an endothermic peak was observed between 325 °C and 400 °C. The end temperature was set too low to obtain a complete endothermic peak. After the experiment, no visual changes could be observed when compared to the original test substance.
The second experiment investigated the endothermic peak between 325 °C and 400 °C, with the end temperature set to 500 °C. An endothermic peak was observed between 350 °C and 450 °C. The extrapolated onset temperature peak was 377.88 °C. A duplicate experiment was conducted and an endothermic peak was obtained between 325 °C and 450 °C. The extrapolated onset temperature of the peak was 372.03 °C.
In the fourth experiment, a repeated heating cycle was applied to investigate the exothermic peak between 325 °C and 450 °C.
With the first heating the extrapolated onset temperature of the endothermic peak was 370.53 °C. During the cooling no exothermic peak was observed. This concluded that the endothermic peak is not obtained through the melting of the test substance. With the second heating no endothermic peak was observed. The endothermic peak in the first instance was probably due to reaction/decomposition of the test substance.
To further investigate the reaction/decomposition of the test substance a lower heating rate of 5 °C/minute was applied in the fifth experiment. The extrapolated onset temperature of the endothermic peak was 344.81 °C, so the endothermic peak shifted to lower temperatures. This demonstrates that reaction/decomposition of the test substance was the reason for the endothermic effect.
In order to obtain a temperature at which the reaction/decomposition starts the sixth experiment was a triplicate of the second and third experiments.
The extrapolated onset temperature of the endothermic peak was 374.05 °C.
The relevant DSC curves are provided in the original study report.
Description of key information
The temperature of decomposition was greater than 320 °C.
An exothermic point was observed at 375.05°C (extrapolated from onset temperature 344.81 °C) - no visual changes observed in comparison to original test substance.
Magnesium hydroxide does not have a melting temperature.
Key value for chemical safety assessment
Additional information
Reaction and/or decomposition of the test substance was observed at temperatures of > 320 °C (> 593 K). Melting of the test substance was not observed below the temperature at which reaction/decomposition started. Therefore the test substance has no melting point.
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