Strontium hexaboride
Chemical compound
From Wikipedia, the free encyclopedia
Strontium boride (SrB6) is an inorganic compound. At room temperature, it appears as a crystalline black powder.[1] Closer examination reveals slightly translucent dark red crystals capable of scratching quartz.[2] It is very stable and has a high melting point and density. Although not thought to be toxic, it is an irritant to the skin, eyes, and respiratory tract.[1]
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| Names | |
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| Other names
strontium hexaboride | |
| Identifiers | |
3D model (JSmol) |
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| ECHA InfoCard | 100.031.778 |
| EC Number |
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PubChem CID |
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CompTox Dashboard (EPA) |
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| Properties | |
| SrB6 | |
| Molar mass | 152.49 g/mol |
| Appearance | black crystalline powder |
| Density | 3.39 g/cm3, solid (15.0°C) |
| Melting point | 2,235 °C (4,055 °F; 2,508 K) |
| insoluble | |
| Structure | |
| Cubic | |
| Pm3m ; Oh | |
| Hazards | |
| NFPA 704 (fire diamond) | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Magnetism
Strontium boride, along with other alkali-earth metal borides, has been shown to exhibit weak ferromagnetism at low temperatures.[3] This is thought by some to be caused by slight impurities or aberrations in the crystal lattice,[4][5] while others suggest different explanations are needed.[6] Strontium boride has also been examined for semiconducting properties at lower temperatures.[7]
Preparation
In his book The Electric Furnace, Henri Moissan describes an early synthesis of strontium boride by mixing strontium borate, aluminum, and carbon in an electric furnace.[2] Alternatively, a solid-phase synthesis of strontium boride can be carried out by reacting two moles of strontium carbonate with three moles of boron carbide and one mole of carbon inside a vacuum furnace.[8]
Uses
Strontium boride is used in insulation and nuclear control rods.[8] A recent patent filed for aircraft windows uses SrB6 nanoparticles in a transparent acrylic sheet. The IR-absorbing properties of these nanoparticles prevents the transmittance of infrared wavelengths while still allowing the transmittance of visible light.[9]