| 词条 | Magnesium fluoride |
| 释义 |
| Watchedfields = changed | verifiedrevid = 477000602 | Name = Magnesium fluoride | Reference = [1] | ImageFile = Rutile-unit-cell-3D-balls.png | ImageSize = | ImageName = Magnesium fluoride | OtherNames = Sellaite Irtran-1 |Section1={{Chembox Identifiers | ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} | ChemSpiderID = 22952 | InChI = 1/2FH.Mg/h2*1H;/q;;+2/p-2 | InChIKey = ORUIBWPALBXDOA-NUQVWONBAK | SMILES = [Mg+2].[F-].[F-] | StdInChI_Ref = {{stdinchicite|correct|chemspider}} | StdInChI = 1S/2FH.Mg/h2*1H;/q;;+2/p-2 | StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} | StdInChIKey = ORUIBWPALBXDOA-UHFFFAOYSA-L | CASNo = 7783-40-6 | CASNo_Ref = {{cascite|correct|CAS}} | PubChem = 24546 | RTECS = OM3325000 | EINECS = 231-995-1 |Section2={{Chembox Properties | Formula = MgF2 | MolarMass = 62.3018{{nbsp}}g/mol | Appearance = White tetragonal crystals | Density = 3.148{{nbsp}}g/cm3 | Solubility = 0.013{{nbsp}}g/100{{thinsp}}mL | SolubilityProduct = 5.16⋅10−11 | SolubleOther = Insoluble in ethanol | MeltingPtC = 1263 | BoilingPtC = 2260 | RefractIndex = 1.37397 | MagSus = −22.7⋅10−6{{nbsp}}cm3/mol }} |Section3={{Chembox Structure | CrystalStruct = Rutile (tetragonal), tP6 | SpaceGroup = P42/mnm, No. 136 |Section4={{Chembox Thermochemistry | DeltaHf = −1124.2{{nbsp}}kJ⋅mol−1 | DeltaHc = | DeltaGf = −1071{{nbsp}}kJ/mol | Entropy = 57.2{{nbsp}}J⋅mol−1⋅K−1 | HeatCapacity = 61.6{{nbsp}}J⋅mol−1⋅K−1 }} |Section7={{Chembox Hazards | Hazards_ref = [2][3] | ExternalSDS = ChemicalBook | GHSPictograms = {{GHS07|Irritant}} | GHSSignalWord = WARNING | HPhrases = {{H-phrases|303|315|319|335}} | PPhrases = {{P-phrases|261|304+340|305+351+338|405}} | LD50 = 2330 (rat, oral) | NFPA-H = 3 | NFPA-F = 0 | NFPA-R = 0 | NFPA-S = }} |Section8={{Chembox Related | OtherAnions = Magnesium chloride Magnesium bromide Magnesium iodide | OtherCations = Beryllium fluoride Calcium fluoride Strontium fluoride Barium fluoride }} Magnesium fluoride is an inorganic compound with the formula MgF2. The compound is a white crystalline salt and is transparent over a wide range of wavelengths, with commercial uses in optics that are also used in space telescopes. It occurs naturally as the rare mineral sellaite. Production and structureMagnesium fluoride is prepared from magnesium oxide with sources of hydrogen fluoride such as ammonium bifluoride: MgO + (NH4)HF2 → MgF2 + NH3 + H2O Related metathesis reactions are also feasible. The compound crystallizes as tetragonal birefringent crystals. The structure of the compound is similar to that in rutile, featuring octahedral Mg2+ centers and 3-coordinate fluoride centres.[4] UsesOpticsMagnesium fluoride is transparent over an extremely wide range of wavelengths. Windows, lenses, and prisms made of this material can be used over the entire range of wavelengths from 0.120 μm (vacuum ultraviolet) to 8.0 μm (infrared). High quality synthetic VUV grade MgF2 is quite expensive, in the region of $3/kg (2007) but the real cost of optics in this material is due to relatively low volume manufacture. However, with lithium fluoride it is one of the two materials that will transmit in the vacuum ultraviolet range at 121 nm (Lyman alpha) and this is where it finds its application. Lower grade MgF2 is sometimes used in the infrared but here it is inferior to calcium fluoride. MgF2 is tough and works and polishes well, but it is slightly birefringent and should be cut with the optic axis perpendicular to the plane of the window or lens.[4] Due to its having a suitable refractive index of 1.37, thin layers of MgF2 are very commonly used on the surfaces of optical elements as inexpensive anti-reflective coatings. The Verdet constant of (MgF2) at 632.8 nm is 0.00810{{nbsp}}arcmin/G⋅cm.[5] SafetyChronic exposure to magnesium fluoride may affect the skeleton, kidneys, central nervous system, respiratory system, eyes and skin, and may cause or aggravate attacks of asthma.[6] References1. ^{{Citation| last = Lide| first = David R.| year = 1998| title = Handbook of Chemistry and Physics| edition = 87| publication-place = Boca Raton, Florida| publisher = CRC Press| isbn = 0-8493-0594-2| pages = 4–67; 1363}} 2. ^{{Cite web|url=http://www.sciencelab.com/msds.php?msdsId=9924548|title=Magnesium Fluoride Material Safety Data Sheet|last=|first=|date=May 21, 2013|website=Science Labs|accessdate=October 13, 2017}} 3. ^{{Cite web|url=http://www.chemicalbook.com/ChemicalProductProperty_EN_CB8716701.htm|title=Magnesium fluoride|last=|first=|date=|website=CAS DataBase List|publisher=ChemicalBook|access-date=October 13, 2017}} 4. ^1 {{citation | first1 = Jean | last1 = Aigueperse | first2 = Paul | last2 = Mollard | first3 = Didier | last3 = Devilliers | first4= Marius | last4 = Chemla | first5 = Robert | last5 = Faron | first6 = Renée | last6 = Romano | first7 = Jean Pierre | last7 = Cuer | contribution = Fluorine Compounds, Inorganic | title = Ullmann's Encyclopedia of Industrial Chemistry | year = 2005 | publisher = Wiley-VCH | place = Weinheim|doi = 10.1002/14356007.a11_307}} 5. ^J. Chem. Soc., Faraday Trans., 1996, 92, 2753 - 2757. {{DOI|10.1039/FT9969202753}} 6. ^{{Cite web|url=http://www.espimetal.com/index.php/msds/658-Magnesium%20Fluoride|title=Magnesium Fluoride Material Safety Data Sheet|last=|first=|date=August 2004|website=ESPI Metals|access-date=October 13, 2017}}{{dead link|date=January 2018|bot=medic}}{{cbignore|bot=medic}} External links
4 : Fluorides|Magnesium compounds|Metal halides|Optical materials |
| 随便看 |
|
开放百科全书收录14589846条英语、德语、日语等多语种百科知识，基本涵盖了大多数领域的百科知识，是一部内容自由、开放的电子版国际百科全书。