noun
definition
The univalent NH4+ cation, derived by the protonation of ammonia
definition
(especially in combination) Any similar cation formed by replacing one or more hydrogen atoms with alkyl or aryl radicals
Examples of ammonium in a Sentence
They may be prepared by the dry distillation of the ammonium salts.
They are precipitated from their alkaline solutions as cobalt sulphide by sulphuretted hydrogen, but this precipitation is prevented by the presence of citric and tartaric acids; similarly the presence of ammonium salts hinders their precipitation by caustic alkalis.
Cobalt ammonium phosphate, CoNH4PO 4.12H 2 0, is formed when a soluble cobalt salt is digested for some time with excess of a warm solution of ammonium phosphate.
By dry distillation it gives ammonium cyanide.
It may be obtained in the spongy form by igniting iridium ammonium chloride, and this variety of the metal readily oxidizes when heated in air.
The reactions are represented as (I) N2+3H2+2C0 -1-2H 2 0=2H CO 2 NH 4 (Ammonium formate).
Similar sodium and ammonium compounds are known.
Stas carried out such experiments on the composition of silver chloride and of ammonium chloride, but he never found a variation of one part in 10,000 in the composition of the substances.
Alkaline carbonates give precipitates of basic carbonates, the formation of which is also retarded by the presence of ammonium salts.
The hexammine salts are formed by the oxidizing action of air on dilute ammoniacal solutions of cobaltous salts, especially in presence of a large excess of ammonium chloride.
It may also be prepared by heating ammonium oxalate; by passing induction sparks between carbon points in an atmosphere of nitrogen.
Boron nitride BN is formed when boron is burned either in air or in nitrogen, but can be obtained more readily by heating to redness in a platinum crucible a mixture of one part of anhydrous borax with two parts of dry ammonium chloride.
Tetramorphism is exhibited by ammonium nitrate.
Ammonium iodide assumes cubic forms with perfect cubic cleavage; tetramethyl ammonium iodide is tetragonal with perfect cleavages parallel to {100} and {o01} - a difference due to the lengthening of the a axes; tetraethyl ammonium iodide also assumes tetragonal forms, but does not exhibit the cleavage of the tetramethyl compound; while tetrapropyl ammonium iodide crystallizes in rhombic form.
In the combined state nitrogen is fairly widely distributed, being found in nitre, Chile saltpetre, ammonium salts and in various animal and vegetable tissues and liquids.
In de Lambilly's process air and steam is led over white-hot coke, and carbon dioxide or monoxide removed from the escaping gases according as ammonium formate or carbonate is wanted.
Soon afterwards, William Cruickshank decomposed the magnesium, sodium and ammonium chlorides, and precipitated silver and copper from their solutions - an observation which led to the process of electroplating.
The dissolved salts (potassium, sodium, ammonium, calcium, magnesium, &c.) of the latex are generally nearly entirely absent from the wellprepared rubber.
Klaproth in the mineral honeystone, which is the aluminium salt of the acid, The acid may be prepared by warming honeystone with ammonium carbonate, boiling off the excess of the ammonium salt and adding ammonia to the solution.
The precipitated alumina is filtered off, the filtrate evaporated and the ammonium salt of the acid purified by recrystallization.
The ammonium salt is then converted into the lead salt by precipitation with lead acetate and the lead salt decomposed by sulphuretted hydrogen.
The mixture may be separated by dissolving out the ammonium euchroate with water.
Ammonium nitrate and nitrite, for instance, intensify the action of a water on lead.
Heating or exposure to sunlight reduces it to the red oxide; it fires when ground with sulphur, and oxidizes ammonia to nitric acid, with the simultaneous formation of ammonium nitrate.
If a suspension of lead dichloride in hydrochloric acid be treated with chlorine gas, a solution of lead tetrachloride is obtained; by adding ammonium chloride ammonium plumbichloride, (NH 4) 2 PbC1 6, is precipitated, which on treatment with strong sulphuric acid yields lead tetrachloride, PbC1 4, as a translucent, yellow, highly refractive liquid.
It is produced by the addition of a solution of lead salt to an excess of ammonium carbonate, as an almost insoluble white precipitate.
Ammonium sulphide blackens it, and it is soluble in solution of ammonium acetate, which distinguishes it from barium sulphate.
The inactive mixture may be resolved into its active components by fractional crystallization of the cinchonine salt, when the salt of the dextro modification separates first; or the ammonium salt may be fermented by Penicillium glaucum, when the laevo form is destroyed and the dextro form remains untouched; on the other' hand, Saccharomyces ellipsoideus destroys the dextro form, but does not touch the laevo form.
Potash alum is the common alum of commerce, although both soda alum and ammonium alum are manufactured.
It is now allowed to stand for some time, decanted from any sediment, and finally mixed with the calculated quantity of potassium sulphate (or if ammonium alum is required, with ammonium sulphate), well agitated, and the alum is thrown down as a finely-divided precipitate of alum meal.
Columbium compounds are usually prepared by fusing columbite with an excess of acid potassium sulphate, boiling out the fused mass with much water, and removing tin and tungsten from the residue by digestion with ammonium sulphide, any iron present being simultaneously converted into ferrous sulphide.
A heavy white precipitate, consisting of ammonium chloride and columbium nitride, is thrown down, and the ammonium chloride is removed by washing it out with hot water, when the columbium nitride remains as an amorphous residue (Hall and Smith, loc. cit.).
The precipitate, after having been collected and washed, is digested with a warm concentrated solution of ammonium carbonate, which dissolves the uranium as a yellow solution of ammonium uranate, while the hydrated oxide of iron, the alumina, &c., remain.
The mother liquor includes generally more or less of nickel, cobalt, zinc and other heavy metals, which, as Wailer showed, can be removed as insoluble sulphides by the addition of ammonium sulphide; uranium, under the circumstances, is not precipitated by this reagent.
Ammonium uranate heated to redness yields pure U308, which serves as a raw material for uranium compounds.
Uranyl nitrate is used in photography, and also in analytical chemistry as a precipitant for phosphoric acid (as uranyl ammonium phosphate, U02 NH4 P04).
Uranyl sulphide, UO 2 S, is a black precipitate obtained by adding ammonium sulphide to a uranyl solution.
Stannous sulphide, SnS, is obtained as a lead-grey mass by heating tin with sulphur, and as a brown precipitate by adding sulphuretted hydrogen to a stannous solution; this is soluble in ammonium polysulphide, and dries to a black powder.
Stannous salt solutions yield a brown precipitate of SnS with sulphuretted hydrogen, which is insoluble in cold dilute acids and in real sulphide of ammonium, (NH 4) 2 S; but the yellow, or the colourless reagent on addition of sulphur, dissolves the precipitate as SnS 2 salt.
Stannic salt solutions give a yellow precipitate of SnS 2 with sulphuretted hydrogen, which is insoluble in cold dilute acids but readily soluble in sulphide of ammonium, and is re-precipitated therefrom as SnS2 on acidification.
The nitrate of this base (known as nitron) is so insoluble that nitrates may be gravimetrically estimated with its help. These bases combine with the alkyl iodides to yield quaternary ammonium salts.
Ammonium hydroxide has no appreciable action at ordinary temperatures, but strong solutions of sodium or potassium hydroxides start a decomposition, with rise of temperature, in which some nitrate and always some nitrite is produced.
It appears that with soils which are not rich in humus or not deficient in lime, calcium cyanamide is almost as good, nitrogen for nitrogen, as ammonium sulphate or sodium nitrate; but it is of doubtful value with peaty soils or soils containing little lime, nor is it usefully available as a top-dressing or for storing.
Iron, zinc, cadmium, also tin under certain conditions, reduce the dilute acid, partially at least, to nitrous oxide, N 2 0, or ammonium nitrate, NH4N03.
In the first stage the ammonium compounds are oxidized to nitrites by the agency of very minute motile bacteria belonging to the genus Nitrosomonas.
Zinc sulphate, like magnesium sulphate, unites with the sulphates of the potassium metals and of ammonium into crystalline double salts, ZnS04 R2S04-+-6H20, isomorphous with one another and the magnesium salts.
In the case of acetate the precipitation is quite complete; from a sulphate or chloride solution the greater part of the metal goes into the precipitate; in the presence of a sufficiency of free HC1 the metal remains dissolved; sulphide of ammonium precipitates the metal completely, even in the presence of ammonium salts and free ammonia.
Titanium trioxide, T103, is obtained as a yellow precipitate by dropping the chloride into alcohol, adding hydrogen peroxide, and finally ammonium carbonate or potash.
Acid solutions of titanates are not precipitated by sulphuretted hydrogen; but ammonium sulphide acts on them as if it were ammonia, the sulphuretted hydrogen being liberated.
The tertiary amines possess the power of combining with one molecular proportion of an alkyl iodide to form quaternary ammonium salts.