Registration Dossier
Registration Dossier
Data platform availability banner - registered substances factsheets
Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.
The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.
Diss Factsheets
Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 231-104-6 | CAS number: 7439-95-4
- 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
Endpoint summary
Administrative data
Description of key information
Additional information
Properties of Magnesium
Physical Properties
(i) Magnesium is a silvery white metal which soon becomes dull in air.
(ii) It is a light metal with a density of 1.74 g cm-3.
(iii)It is fairly malleable and ductile.
Chemical Properties
(i) Action of oxygen or air
Magnesium does not react with dry air but slowly gets tarnished in most air due to the formation of a thin film of the oxide, MgO. It burns in oxygen or air with a dazzling light.
Δ
2Mg + O2 ——→ 2MgO
(ii) Action of CO2 and SO2
Because of its great affinity for oxygen magnesium keeps on burning even in CO2 or SO2.
Δ
2Mg + CO2 ——→ 2MgO + C
Δ
2Mg + SO2 ——→ 2MgO + S
(iii) Action of nitrogen
On heating magnesium combines with nitrogen to form magnesium nitride.
3Mg + N2 ——→ Mg3N2
Thus when magnesium burns in air both the oxide and the nitride are formed.
(iv) Action of halogens
Magnesium on heating with halogens readily forms the halides e.g.
Δ
Mg + CI2 ——→ MgCI2
(v) Action of water
Magnesium does not decompose water in cold but decomposes boiling water or steam.
Mg + H2O ( steam) ——→ MgO + H2
(vi) Action of Acids
Dilute acids reacts with magnesium to produce dihydrogen.
Mg + 2HCI ——→ MgCi2 + H2
Mg + H2SO4 ——→ MgSO4 + H2
(dil)
Mg + 2HNO3 ——→ Mg ( NO3)2 + H2
However with conc. H2SO4, SO2 is produced
Mg + 2H2SO4 ——→ MgSo4 + SO2 + 2H2O
(conc.)
(vii) Reaction with alkyl halide
Magnesium reacts with alkyl halides in dry ether to form covalent compound called Grignard reagent.
Dry ether
Mg + C2H5I ——→C2H5MgI
Uses of Magnesium
(i) The chief use of magnesium is in the preparation of alloys with aluminum, zinc, manganese and tin.
Duralium (Al = 95%, Cu = 4%. Mn = 0.5%, Mg = 0.5%)
Mangnalium (Al = 90% & Mg = 10%)
Duralium being light, tough and durable is used for the manufacture of airplanes and automobiles parts. Magnalium being light, tough and hard is used for making balance beams.
(ii) Magnesium burns with an intense lights, therefore, Mg (as power or ribbon) is used in flash bulbs for photography, fireworks and signals fibres.
(iii) Mg is used for ignition of thermite charge in aluminothermy.
(iv) A suspension of magnesium hydroxide known as milk of magnesium is used as an antacid for patients suffering from acidity.
(v) In preparation of Grignard reagent.
(vi)Being a reducing agent, magnesium is used in the extraction of boron and silicon from their respective oxides.
B2O3 + 3Mg ——→ 3 MgO + 2B
SiO2 + 2Mg ——→ 2MgO + Si
Minerals of magnesium are:
(i) Magnesite– MgCO3
(ii) Dolomite– MgCO3.CaCO3
(iii) Epsom salt – MgSO4.7H2O
(iv) Carnallite – KCl.MgCl2.6H2O
Magnesium Metal
Magnesium occurs as magnesite MgCO3, dolomite CaMg(CO3)2, Epsomite (MgSO4.7H2O) and carnalite K2MgCl4.6H2O and langbeinite K2Mg2(SO4)3 deposits. The chloride and sulphate of magnesium occurs in sea water from which it being extracted on an increasing scale.
Extraction
(a) From magnesite or Dolomite
The ore is first calcined to form the oxide
MgCO3 → MgO + CO2
CaCO3.MgCO3 → CaO.MgO + 2CO2
The metal is obtained from the oxide or the mixed oxides as follows:
(i) From MgO:
The oxide is mixed with carbon and heated in a current of chlorine gas.
MgO + C + Cl2 → MgCl2 + CO
The chloride thus obtained is subjected to electrolysis.
(ii) The mixed oxides [CaO.MgO] obtained from calcination of Dolomite [CaCO3.MgCO3] are redcued by ferrosilicon under reduced pressure above 1273 K.
2CaO + 2MgO + FeSi → 2Mg + Fe + Ca2SiO4
(b) From Carnallite
The ore is dehydrated in a current of hydrogen chloride and the mixture of fused chloride is electrolysed.
(c) From Sea water
Sea water containing magnesium chloride is concentrated under the sun and is treated with calcium hydroxide Ca(OH)2. Mg(OH)2 is thus precipitated, filtered and heated to give the oxide.
The oxide so obtained is treated as in (a) (i) above and then electrolysed.
Electrolysis of Magnesium Chloride
MgCl2 obtained by any of the above methods is fused and mixed with additional mixture of NaCl and CaCl2 in the temperature range of 973 – 1023 K. The molten mixture is electrolysed. Magnesium is liberated at the cathode and chlorine is evolved at the anode.
At cathode: Mg+2 + 2e- → Mg
At cathode: 2Cl- → Cl2 + 2e-
Electrolysis of Magnesium Chlorine
A stream of coal gas is blown through the cell to prevent oxidation of Mg metal. Mg metal is obtained in liquid state which is further distilled to give pure magnesium.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.