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Encyclopedia > Hydrogen selenide
Hydrogen selenide
Systematic name Hydrogen selenide
Other names Hydroselenic acid
selenium hydride
Molecular formula H2Se
Molar mass 80.9758 g/mol
Appearance Colorless gas.
CAS number [7783-07-5]
Density and phase 3.310 g/l, gas.
Solubility in water 0.70 g/100 mL
Melting point -65.73°C (207.42 K)
Boiling point -41.25°C (231.9 K)
Acidity (pKa) 3.89 (11.0 at 25C)
Molecular shape Planar.
Dipole moment  ? D
MSDS External MSDS
Main hazards Highly toxic, highly
flammable, corrosive
NFPA 704
Flash point  ?°C
R/S statement R: R11, R24, R26
S: ?
RTECS number X1050000
Supplementary data page
Structure and
n, εr, etc.
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
Related compounds
Other group 16
hydrogen compounds
Other selenides Ag2Se
Related compounds OSeCl2
Except where noted otherwise, data are given for
materials in their standard state (at 25°C, 100 kPa)
Infobox disclaimer and references

Hydrogen selenide is H2Se, the simplest hydride of selenium. H2Se is a colorless, flammable gas under standard conditions. It is the most toxic selenium compound with an exposure limit: 0.3 ppm over an 8 hour period. Image File history File links Size of this preview: 800 × 471 pixelsFull resolution (1100 × 648 pixel, file size: 54 KB, MIME type: image/png) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Hydrogen selenide ... Image File history File links Download high-resolution version (1084x1100, 248 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Hydrogen selenide User:Benjah-bmm27/Gallery/Hydrogen ... IUPAC nomenclature is a system of naming chemical compounds and of describing the science of chemistry in general. ... This article does not cite its references or sources. ... Molar mass is the mass of one mole of a chemical element or chemical compound. ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... In physics, density is mass m per unit volume V. For the common case of a homogeneous substance, it is expressed as: where, in SI units: ρ (rho) is the density of the substance, measured in kg·m-3 m is the mass of the substance, measured in kg V is... In the physical sciences, a phase is a set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties (i. ... Solubility refers to the ability for a given substance, the solute, to dissolve in a solvent. ... “HOH” redirects here. ... The melting point of a crystalline solid is the temperature at which it changes state from solid to liquid. ... The boiling point of a substance is the temperature at which it can change its state from a liquid to a gas throughout the bulk of the liquid at a given pressure. ... The acid dissociation constant (Ka), also known as the acidity constant or the acid-ionization constant, is a specific equilibrium constant for the reaction of an acid with its conjugate base in aqueous solution [1]. // When an acid dissolves in water, it partly dissociates forming hydronium ions and its conjugate... four sp³ orbitals three sp² orbitals In chemistry, hybridisation or hybridization (see also spelling differences) is the concept of mixing atomic orbitals to form new hybrid orbitals suitable for the qualitative description of atomic bonding properties. ... The Earths magnetic field, which is approximately a dipole. ... The debye (symbol: D) is a non-SI and non-CGS unit of electrical dipole moment. ... An example MSDS in a US format provides guidance for handling a hazardous substance and information on its composition and properties. ... The examples and perspective in this article or section may not represent a worldwide view. ... NFPA 704 is a standard maintained by the U.S. National Fire Protection Association. ... Image File history File links NFPA_704. ... The flash point of a flammable liquid is the lowest temperature at which it can form an ignitable mixture with air. ... Risk and Safety Statements, also known as R/S statements, R/S numbers, R/S phrases, and R/S sentences, is a system of hazard codes and phrases for labeling dangerous chemicals and compounds. ... R-phrases are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous substances and preparations. ... S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. ... RTECS, also known as Registry of Toxic Effects of Chemical Substances, is a database of toxicity information compiled from the open scientific literature that is available for charge. ... The refractive index (or index of refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves) is reduced inside the medium. ... The relative dielectric constant of a material under given conditions is a measure of the extent to which it concentrates electrostatic lines of flux. ... Ultraviolet-Visible Spectroscopy or Ultraviolet-Visible Spectrophotometry (UV/ VIS) involves the spectroscopy of photons (spectrophotometry). ... Infrared spectroscopy (IR Spectroscopy) is the subset of spectroscopy that deals with the IR region of the EM spectrum. ... Nuclear Magnetic Resonance Spectroscopy most commonly known as NMR Spectroscopy is the name given to the technique which exploits the magnetic properties of nuclei. ... Mass spectrometry (also known as mass spectroscopy (deprecated)[1] or informally, mass-spec and MS) is an analytical technique used to measure the mass-to-charge ratio of ions. ... “HOH” redirects here. ... Hydrogen sulfide (hydrogen sulphide in British English), H2S, is a colorless, toxic, flammable gas that is responsible for the foul odor of rotten eggs and flatulence. ... Hydrogen telluride is H2Te, the simplest hydride of tellurium. ... The selenide ion is Se2-. A selenide is a chemical compound in which selenium serves as a anion with oxidation number of -2, much as sulfur does in a sulfide. ... This article or section is in need of attention from an expert on the subject. ... Selenium oxydichloride is the chemical compound SeOCl2, a close chemical relative of thionyl chloride, SOCl2. ... In chemistry, the standard state of a material is its state at 1 bar (100 kilopascals) and 25 degrees Celsius (298. ... A hydride is a compound of hydrogen with more electropositive elements. ... Se redirects here. ... Parts per million (ppm) is a measure of concentration that is used where low levels of concentration are significant. ...



H2Se adopts a "bent" structure with a H-Se-H bond angle of 91°. Consistent with this structure, three IR-active vibrational bands are observed: 2358, 2345, and 1034 cm-1. Image of two girls in mid-infrared (thermal) light (false-color) Infrared (IR) radiation is electromagnetic radiation of a wavelength longer than that of visible light, but shorter than that of radio waves. ...


The properties of H2S and H2Se are similar, although the selenide is more acidic with pKa = 3.89, and the second pKa = 11.0 at 25°C. Reflecting its acidity, H2Se is soluble in water. Hydrogen sulfide (hydrogen sulphide in British English), H2S, is a colorless, toxic, flammable gas that is responsible for the foul odor of rotten eggs and flatulence. ...


H2Se can be purchased in cylinders. A number of routes to H2Se have been reported, which are suitable for both large and small scale preparations.

  • H2Se is usually prepared by the action of water on Al2Se3, concomitant with formation of hydrated alumina. A related reaction involves the acid hydrolysis of FeSe.
Al2Se3 + 6 H2O 2 Al(OH)3 + 3 H2Se
  • According to the Sonoda method, H2Se is generated from the reaction of H2O and CO on Se in the presence of Et3N.
  • H2Se can by synthesized by the direct reaction of H2 with elemental selenium at >350°C.

Selenium metal can be recovered from H2Se through a reaction with aqueous sulfur dioxide (SO2). Aluminium oxide (or aluminum oxide) (Al2O3) is a chemical compound of aluminium and oxygen. ... Se redirects here. ... Sulfur dioxide (or Sulphur dioxide) has the chemical formula SO2. ...

2 H2Se + SO2 2 H2O + Se + S


  • H2Se is commonly used in the synthesis of Se-containing compounds; it adds across alkenes. Illustrative is the synthesis of selenoureas from nitriles.

Selenourea reaction Image File history File links SelenoureaRxn1. ...

  • H2Se gas is used to dope semiconductors with selenium.

In semiconductor production, doping refers to the process of intentionally introducing impurities into an extremely pure (also referred to as intrinsic) semiconductor in order to change its electrical properties. ...


  1. Patnaik, Pradyot Handbook of Inorganic Chemicals. McGraw-Hill Handbooks New York (2003).
  2. V.I. Cohen, Synthesis 1:60-3 (1980).
  3. Greenwood, N. N., Earnshaw, A. Chemistry of the Elements Second Ed. Butterworth-Heinemann, Boston (1997).
  4. CRC Handbook of Chemistry and Physics Ed. 82. Chapman and Hall (2001-2002).
  • Feher, 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

  • Links to external chemical sources

  Results from FactBites:
hydrogen sulfide: Definition and Much More from Answers.com (2204 words)
Hydrogen sulfide reacts with most metal ions to form sulfides; the sulfides of some metals are insoluble in water and have characteristic colors that help to identify the metal during chemical analysis.
Hydrogen sulfide is corrosive and renders some steels brittle, leading to sulphide stress cracking - a concern especially for handling acid gas and sour crude oil in the oil industry.
Hydrogen sulfide is a central participant in the sulfur cycle, the biogeochemical cycle of sulfur on Earth.
RIA - Hydrogen selenide (1619 words)
Hydrogen selenide may be produced as a by-product and liberated during processes where selenium compounds may be present for example, during the smelting of alloys, during lead battery manufacture and during the production of studio glass.
The OES for hydrogen selenide i.e 0.05 ppm 8-hour TWA has been withdrawn and in the meantime until a MEL is assigned to the gas, ACTS considers that the general requirement on employers under the Control of Substances Hazardous to Health (COSHH) Regulations 1999 will ensure adequate control of exposure to this substance.
Hydrogen selenide may also be produced as a by-product where selenium compounds are present such as during alloy smelting but it is expected to be negligible because of the relatively trace amounts of selenium likely to be present in the parent selenium.
  More results at FactBites »



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