Hydrogen selenide 2208941 200655144 2008-03-24T22:39:32Z Benjah-bmm27 126395 images side-by-side {{Chembox new | Name = Hydrogen selenide | ImageFileL1 = Hydrogen-selenide-2D-dimensions.png | ImageSizeL1 = 130px | ImageNameL1 = Structural diagram of the hydrogen selenide molecule | ImageFileR1 = Hydrogen-selenide-3D-vdW.png <!-- | ImageSizeR1 = 120px --> | ImageNameR1 = Space-filling model of the hydrogen selenide molecule | IUPACName = Hydrogen selenide | OtherNames = Hydroselenic acid<br />selane<br />selenium hydride | Section1 = {{Chembox Identifiers | CASNo = 7783-07-5 | RTECS = X1050000 }} | Section2 = {{Chembox Properties | Formula = H<sub>2</sub>Se | MolarMass = 80.9758 g/mol | Appearance = Colorless gas. | Density = 3.310 g/l, gas. | Solubility = 0.70 g/100 mL | MeltingPt = -65.73°C (207.42 K) | BoilingPt = -41.25°C (231.9 K) | pKa = ''3.89 (11.0 at 25C)'' }} | Section3 = {{Chembox Structure | MolShape = Bent | Dipole = }} | Section7 = {{Chembox Hazards | ExternalMSDS = | MainHazards = Highly toxic, highly<br />flammable, corrosive | NFPA-H = 4 | NFPA-R = 3 | NFPA-F = 4 | FlashPt = ?°C | RPhrases = {{R11}}, {{R24}}, {{R26}} | SPhrases = }} | Section8 = {{Chembox Related | OtherAnions = | [[water (molecule)|H<sub>2</sub>O]]<br />[[hydrogen sulfide|H<sub>2</sub>S]]<br />[[hydrogen telluride|H<sub>2</sub>Te]]<br />[[hydrogen polonide|H<sub>2</sub>Po]] | OtherCpds = [[selenium oxydichloride|OSeCl<sub>2</sub>]] | OtherCations = [[silver(I) selenide|Ag<sub>2</sub>Se]] }} }} '''Hydrogen selenide''' is H<sub>2</sub>Se, the simplest [[hydride]] of [[selenium]]. H<sub>2</sub>Se is a colorless, flammable gas under standard conditions. It is the most toxic selenium compound with an exposure limit: 0.3 [[parts per million|ppm]] over an 8 hour period. This compound has a very irritating smell of decayed [[horseradish]]. ==Structure== H<sub>2</sub>Se adopts a "bent" structure with a H-Se-H bond angle of 91°. Consistent with this structure, three [[Infrared|IR]]-active vibrational bands are observed: 2358, 2345, and 1034 cm<sup>−1</sup>. ==Properties== The properties of [[Hydrogen sulfide|H<sub>2</sub>S]] and H<sub>2</sub>Se are similar, although the selenide is more acidic with p''K''<sub>a</sub> = 3.89, and the second p''K''<sub>a</sub> = 11.0 at 25°C. Reflecting its acidity, H<sub>2</sub>Se is soluble in water. ==Preparation== H<sub>2</sub>Se can be purchased in cylinders. A number of routes to H<sub>2</sub>Se have been reported, which are suitable for both large and small scale preparations. *H<sub>2</sub>Se is usually prepared by the action of water on Al<sub>2</sub>Se<sub>3</sub>, concomitant with formation of hydrated [[alumina]]. A related reaction involves the acid hydrolysis of FeSe. ::Al<sub>2</sub>Se<sub>3</sub> + 6 H<sub>2</sub>O {{unicode|⇌}} 2 Al(OH)<sub>3</sub> + 3 H<sub>2</sub>Se *According to the Sonoda method, H<sub>2</sub>Se is generated from the reaction of H<sub>2</sub>O and CO on Se in the presence of Et<sub>3</sub>N. *H<sub>2</sub>Se can by synthesized by the direct reaction of H<sub>2</sub> with elemental [[selenium]] at >350°C. Selenium metal can be recovered from H<sub>2</sub>Se through a reaction with aqueous [[sulfur dioxide]] (SO<sub>2</sub>). ::2 H<sub>2</sub>Se + SO<sub>2</sub> {{unicode|⇌}} 2 H<sub>2</sub>O + Se + S ==Applications== *H<sub>2</sub>Se is commonly used in the synthesis of Se-containing compounds; it adds across alkenes. Illustrative is the synthesis of selenoureas from nitriles. [[Image:SelenoureaRxn1.PNG|350px|Selenourea reaction]] *H<sub>2</sub>Se gas is used to [[doping (semiconductor)|dope]] semiconductors with selenium. ==References== {{Citationstyle|date=September 2007}} <references/> #Patnaik, Pradyot ''Handbook of Inorganic Chemicals''. McGraw-Hill Handbooks New York (2003). #V.I. Cohen, ''Synthesis'' 1:60-3 (1980). #Greenwood, N. N., Earnshaw, A. ''Chemistry of the Elements Second Ed.'' Butterworth-Heinemann, Boston (1997). #''CRC Handbook of Chemistry and Physics Ed. 82''. Chapman and Hall (2001-2002). #Féher, F. In "Handbook of Preparative Inorganic Chemistry"; Brauer, E., Ed.; Academic: New York, 1963; 1, p 418. #Sonoda, N.; Kondo K.; Nagano, K.; Kambe, N.; Morimoto, F. Angewandte Chemie, International Edition English 1980, vol. 19, page 308 ==External links== * [http://www.webelements.com/webelements/compounds/text/H/H2Se1-7783075.html WebElements page on compound's properties] [[Category:Hydrogen compounds]] [[Category:Selenides]] [[de:Selenwasserstoff]] [[it:Seleniuro di idrogeno]] [[ja:セレン化水素]] [[pl:Selenowodór]] [[ru:Селеноводород]]