Selenide, potassium sodium hydrogen

Hydrogen cyanide Calcium cyanide Potassium cyanide Sodium cyanide Hydrogen fluoride as F Hydrogen peroxide Hydrogen selenide as Se Hydrogen sulphide Hydroquinone... 

Potassium selenides.—The monoselenide, K2Se, is formed by the action of selenium on excess of potassium dissolved in liquid ammonia with excess of selenium the tetraselenide, KjSe is produced.3 Each compound resembles the corresponding sodium derivative. With solutions of potassium carbonate, hydrogen selenide reacts forming a number of hydrates of the monoselenide. The heat of formation of the anhydrous mono-derivative is given as 79-4 Cal.4 The triselenide has been isolated,5 and Fabre has also described the primary selenide, KSeH. 

Ignition on contact with furfuryl alcohol powdered metals (e.g., magnesium iron) wood. Violent reaction with aluminum isopropoxide -f- heavy metal salts charcoal coal dimethylphenylphosphine hydrogen selenide lithium tetrahydroaluminate metals (e.g., potassium, sodium, lithium) metal oxides (e.g., cobalt oxide, iron oxide, lead oxide, lead hydroxide, manganese oxide, mercur oxide, nickel oxide) metal salts (e.g., calcium permanganate) methanol + phosphoric acid 4-methyl-2,4,6-triazatricyclo [5.2.2.0 ] undeca-8-ene-3,5-dione + potassium hydroxide a-phenylselenoketones phosphorus phosphorus (V) oxide tin(II) chloride unsaturated organic compounds. 

In aprotic solvents, such as dichloromethane and THF, potassium boro-hydride [10], lithium borohydride [8b], lithium triethylborohydride [8a, 11], and diisobutylaluminum hydride (DIBALH) [11] have been used instead of NaBH4. NaBH4 also reduces elemental selenium in alcohol or water to sodium hydrogen selenide or sodium diselenide (Na2Se2) depending on the stoichiometry of the reactants (Scheme 8) [12]. These anions are useful for the synthesis of selenides or diselenides, respectively, via nucleophilic substitution with various electrophiles. 

Selenophens.— The preparation of selenophen by the action of sodium hydrogen selenide on bis(trimethylsilyl)butadiyne, Me3SiC=C—C=CSiMe3, has been described. The reaction of dimethyl acetylenedicarboxylate with the potassium salt PhC=CSe yields the ester (270), together with a little of the diselenole (271). Treatment of dibenzylideneacetone with selenium tetrabromide gives compound (272), which is converted into the benzoselenophen (273 R = COCH=CHPh) in the presence of pyridine.The ester (273 R = C02Et) has been obtained by cyclization of ethyl o-methylselenocinnamate (274) by means of bromine and pyridine. 

Selenocyanic Acid, HCNSe, may be prepared in solution by decomposing the lead salt (obtained by treating potassium selenocyanate with lead acetate) with hydrogen sulphide.3 It is stable only in neutral or alkaline solution. Selenocyanuric acid has been obtained 4 as a red amorphous powder by the action of cyanuric chloride on sodium selenide and subsequent precipitation by acids. 

A large number of 3-pyrazolin-5-thiones and a few 5-seleno analogs (Table XVIII) have been prepared. Almost all of these have been synthesized by reaction of the methochloride or methiodide of a 3- or 5-halogenated pyrazole with potassium hydrogen sulfide,844,984,986,988,992 potassium sulfide, sodium sulfide901 or potassium hydrogen selenide.986 This method of synthesis is illustrated in eq. 149 for a 5-halopyrazole. 

Concordant results were obtained for Reaction 2 with the lithium, sodium, and potassium hydroxides. The data yield with selected auxiliary data the following estimate of the standard enthalpy of formation of the hydrogen selenide ion, Af//° (HSe , 298.15 K) = (14.3 3.2) kJ-mol. ... 

EXPLOSION and FIRE CONCERNS combustible solid NFPA rating (NA) reacts to form explosive products with metal amides contact with acids may cause formation of poisonous hydrogen selenide gas incompatible or reacts violently with barium carbide, bromine pen-tafluoride, chromic oxide, fluorine, lithium carbide, lithium silicon, metals, nickel, sodium, nitric acid, nitrogen trichloride, oxygen, potassium, potassium bromate, rubidium carbide, zinc, silver bromate, uranium, strontium carbide, and thorium carbide toxic gases and vapors may be released in a fire involving selenium, sodium selenite, sodium selenate, and selenium dioxide use water for firefighting purposes. 

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