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Magnesium chlorate

Names
IUPAC name Magnesium dichlorate hexahydrate
Systematic IUPAC name Magnesium dichlorate
Other names Magnesium(II) chlorate
Identifiers
CAS Number	10326-21-3 (dihydrate): 36355-97-2 (hexahydrate): 7791-19-7
3D model (JSmol)	Interactive image (dihydrate): Interactive image (hexahydrate): Interactive image
ChemSpider	64853748 (dihydrate): 80564724 (hexahydrate): 128878
ECHA InfoCard	100.030.634
EC Number	233-711-1
PubChem CID	25155 (dihydrate): 71437298 (hexahydrate): 146100
UNII	M536P01U3N
UN number	2723
CompTox Dashboard (EPA)	DTXSID30890653 (hexahydrate): DTXSID30999110
InChI InChI=1S/2ClHO3.Mg/c2*2-1(3)4;/h2*(H,2,3,4);/q;;+2/p-2Key: NNNSKJSUQWKSAM-UHFFFAOYSA-L (dihydrate): InChI=1S/2ClHO3.Mg.2H2O/c2*2-1(3)4;;;/h2*(H,2,3,4);;2*1H2/q;;+2;;/p-2Key: YTXOASNCVSJHNM-UHFFFAOYSA-L (hexahydrate): InChI=1S/2ClHO3.Mg.6H2O/c2*2-1(3)4;;;;;;;/h2*(H,2,3,4);;6*1H2/q;;+2;;;;;;/p-2Key: XKPLAISKKLSAQQ-UHFFFAOYSA-L
SMILES Cl(=O)(=O).Cl(=O)(=O). (dihydrate): O.O..Cl(=O)=O.Cl(=O)=O (hexahydrate): O.O.O.O.O.O.Cl(=O)=O.Cl(=O)=O.
Properties
Chemical formula	Mg(ClO3)2
Molar mass	191.20 g/mol
Appearance	White crystalline solid
Density	1.747 g/cm (hexahydrate)
Melting point	35 °C (95 °F; 308 K)
Boiling point	120 °C (248 °F; 393 K) (decomposition)
Solubility in water	114 g/100 ml (0 °C) 123 g/100 ml (10 °C) 135 g/100 ml (20 °C) 155 g/100 ml (30 °C) 178 g/100 ml (50 °C) 242 g/100 ml (60 °C) 268 g/100 ml (100 °C)
Solubility in acetone	Soluble
Structure
Crystal structure	Monoclinic
Space group	P21/c
Lattice constant	a = 6.39 Å, b = 6.51 Å, c = 13.90 Åα = 90°, β = 100.3°, γ = 90°
Lattice volume (V)	590.1 Å
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H302, H332
Lethal dose or concentration (LD, LC):
LD50 (median dose)	6348 mg/kg (rat, oral)
Related compounds
Other cations	Calcium chlorate Strontium chlorate Barium chlorate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). Infobox references

Magnesium chlorate refers to inorganic compounds with the chemical formula Mg(ClO₃)₂(H₂O)_x. The anhydrous (x = 0), dihydrate (x = 2), and hexahydrate (x = 6) are known. These are thermally labile white solids. The hexahydrate has been identified on the Martian surface.

Production

Samples of magnesium chlorate were first claimed in 1920 as the result of treating magnesium oxide with chlorine. A more modern method involves electrolysis of magnesium chloride. The magnesium chlorate can be purified by exploiting its solubility in acetone.

Properties

The hexahydrate Mg(ClO₃)₂·6H₂O decomposes to the tetrahydrate at 35 °C. At 65 °C, it dehydrates to the dihydrate, then at 80 °C forms a basic salt. If further heated to 120 °C it decomposes to water, oxygen, chlorine, and magnesium oxide.

As confirmed by X-ray crystallography, the di- and hexahydrates feature octahedral Mg centers. The other ligands are water, exclusively in the hexahydrate. In the dihydrate, chlorate is also coordinated and functions as a bridging ligand.

Uses

Magnesium(II) chlorate is used as a powerful desiccant and a defoliant for cotton, potato, and rice. It is also found as a lubricant in eye drops as an inactive ingredient.

Hazards

Magnesium chlorate is an oxidizer and can in principle form explosive mixtures.

References

1. ^ Kossev, K; Tsvetanova, L.; Dimowa, L.; Nikolova, R.; Shivachev, B. (2013). "Synthesis and Crystal Structure of Magnesium Chlorate Dihydrate and Magnesium Chlorate Hexahydrate". Bulgarian Chemical Communications. 45: 543–548.
2. ^ Joseph William Mellor (1922). Supplement to Mellor's Comprehensive Treatise on Inorganic and Theoretical Chemistry: suppl. 3. K, Rb, Cs, Fr. Longmans, Green and Company.
3. Ojha, Lujendra; Wilhelm, Mary Beth; Murchie, Scott L.; McEwen, Alfred S.; Wray, James J.; Hanley, Jennifer; Massé, Marion; Chojnacki, Matt (2015). "Spectral evidence for hydrated salts in recurring slope lineae on Mars". Nature Geoscience. 8 (11): 829–832. Bibcode:2015NatGe...8..829O. doi:10.1038/ngeo2546.
4. ^ Herbert Maxim (1948). The electrolytic production of magnesium chlorate and perchlorate. the Department of Chemical Engineering: University of Southern California.
5. "MAGNESIUM CHLORATE". National Center for Advancing Translational Sciences. U.S. Department of Health & Human Services. Retrieved 27 August 2021.

• Magnesium compounds
• Chlorates