A few drops of starch solution are then added, and when the blue colour has nearly vanished a drop or two of methyl orange makes the end reaction very sharp. The thiosulphate solution is standardized by dissolving o 3 to o 5 gramme of pure copper in 3 cc. of nitric acid, adding 50 cc. of water and 5 cc. of ammonia, and titrating as above after the addition of 5 cc. of glacial acetic acid and 5 cc. of the potassium iodide solution.
A pentasulphide B2S5 is prepared, in an impure condition, by heating a solution of sulphur in carbon bisulphide with boron iodide, and forms a white crystalline powder which decomposes under the influence of water into sulphur, sulphuretted hydrogen and boric acid.
Aeuer (Ber., 1904, 37, p. 2 53 6; Ann., 1904, 337, p. 362), who converted pure ethyl iodide into hydriodic acid and subsequently into silver iodide, which they then analysed, obtained the value 126.026 (H =1); a discussion of this and other values gave as a mean 126.97 (0=16).
Alcohols may be readily prepared from the corresponding alkyl haloid by the action of moist silver oxide (which behaves as silver hydroxide); by the saponification of their esters; or b the reduction of of h dric alcohols by P Y Y with hydriodic acid, and the subsequent conversion of the resulting alkyl iodide into the alcohol by moist silver oxide.
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.
Ammonium iodide, NH 4 I, can be prepared by the action of hydriodic acid on ammonia.
As a general rule the modification stable at higher temperatures possesses a lower density; but this is by no means always the case, since the converse is true for antimonious and arsenious oxides, silver iodide and some other substances.
As a rule it is preferable to use iodine in the presence of a carrier, such as amorphous phosphorus or ferrous iodide or to use it with a solvent.
As an elementary substance, it is very similar in its physical properties to lead; it resembles lead chemically inasmuch as it forms an almost insoluble chloride and an insoluble iodide.
Aurous iodide is also obtained as a green solid by acting upon gold with iodine.
Aurous iodide, Aul, is a light-yellow, sparingly soluble powder obtained, together with free iodine, by adding potassium iodide to auric chloride; auric iodide, Au13, is formed as a dark-green powder at the same time, but it readily decomposes to aurous iodide and iodine.
Bismuth trifluoride, BiF3, a white powder, bismuth tribromide, BiBr 3, golden yellow crystals, bismuth iodide, Bi13, greyish-black crystals, are also known.
Boron and iodine do not combine directly, but gaseous hydriodic acid reacts with amorphous boron to form the iodide, BI 31 which can also be obtained by passing boron chloride and hydriodic acid through a red-hot porcelain tube.
Both the iodide and bromide are used in photography.
By distilling an alloy of antimony and sodium with mythyl iodide, mixed with sand, trimethyl stibine, Sb(CH 3) 3 i is obtained; this combines with excess of methyl iodide to form tetramethyl stibonium iodide, Sb(CH 3) 4 1.
By passing the vapour of this compound through a red-hot tube, it yields the isomeric a0- pyridylpyrrol, the potassium salt of which with methyl iodide gives a substance methylated both in the pyridine and pyrrol nuclei.
C 6 H 7 0, is obtained by condensing sodium aceto-acetate with methylene iodide, the ester so formed being then hydrolysed.
Calcium iodide and bromide are white deliquescent solids and closely resemble the chloride.
Canine is a secondary base, forming a nitroso derivative with nitrous acid, a urethane with chlorcarbonic ester and a tertiary base (methyl conine) with methyl iodide; reactions which point to the presence of the = NH group in the molecule.
Cerous bromide, 2CeBr 3.3H 2 O, and iodide, CeI 3.9H 2 O, are known.
Commercial iodine may be purified by mixing it with a little potassium iodide and then subliming the mixture; in this way any traces of bromine or chlorine are removed.
Conspicuous examples are afforded by oxygen, carbon, boron, silicon, phosphorus, mercuric oxide and iodide.
Conversely, by heating protocatechuic acid with potash and methylene iodide, piperonylic acid was regained.
Cupric iodide is only known in combination, as in Cu12, 4NH 31 H 2 O, which is obtained by exposing Cu 2 I 2, 4NH 3 to moist air.
Cuprous iodide, Cu 2 l 21 is obtained as a white powder, which suffers little alteration on exposure, by the direct union of its components or by mixing solutions of cuprous chloride in hydrochloric acid and potassium iodide; or, with liberation of iodine, by adding potassium iodide to a cupric salt.
Cyanogen iodide and iodine monoand tri-chloride effect similar decompositions with simultaneous liberation of iodine; sulphuric acid reacts slowly, forming nickel sulphate and liberating hydrogen and carbon monoxide.
Decker (Ber., 9 5, 38, p. 1144) has found that many ortho substituted quinolines will not combine with methyl iodide owing to steric hindrance, but the difficulty can be overcome in most cases by using methyl sulphate and heating the reaction components to ioo C. for half an hour.
Dietary supplementation (as sodium iodide) may be needed to prevent the hypothyroidism in these cases.
Ethylidene succinic acid or isosuccinic acid, CH3 CH(C02H)2, is produced by the hydrolysis of a-cyanpropionic acid and by the action of methyl iodide on sodio-malonic ester.
Euler (Ber., 97, 30, 1989) by distilling the addition compound of methyl iodide and 2 3 5-trimethylpyrollidine with caustic potash.
Fe2P3 is prepared by the action of phosphorus iodide vapour on reduced iron.
Ferric iodide does not appear to exist.
Ferrous iodide, FeI2, is obtained as a grey crystalline mass by the direct union of its components.
Finally, 1 to 2 grams of potassium iodide, dissolved in a little water, are added to produce a clearer film.
For certain concentrated solutions the transport number is found to be greater than unity; thus for a normal solution of cadmium iodide its value is I 12.
For examining root tips we often counterstain cell walls for a few minutes with 10 ug/ml propidium iodide solution.
For the so-called nitrogen iodide see Ammonia.
From solutions containing it as thallous salt the metal is easily precipitated as chloride, iodide, or chloroplatinate by the corresponding reagents.
From the alloy containing 25% of silicon, the excess of magnesium is removed by a mixture of ethyl iodide and ether and a residue consisting of slate-blue octahedral crystals of magnesium silicide is left.
From this iodide the trimethyl stibine may be obtained by distillation with an alloy of potassium and antimony in a current of carbon dioxide.
Grignard (Comptes Rendus, 1900 et seq.) showed that aldehydes combine with magnesium alkyl iodides (in absolute ether solution) to form addition products, which are decomposed by water with the formation of secondary alcohols, thus from acetaldehyde and magnesium methyl iodide, isopropyl alcohol is obtained.
Henri Moissan obtained the metal of 99% purity by electrolysing calcium iodide at a low red heat, using a nickel cathode and a graphite anode; he also showed that a more convenient process consisted in heating the iodide with an excess of sodium, forming an amalgam of the product, and removing the sodium by means of absolute alcohol (which has but little action on calcium), and the mercury by distillation.
Henry started with methyl iodide, the formula of which we write in the form CI a H b H c H d.
Hydriodic acid and the iodides may be estimated by conversion into silver iodide.
Hydriodic acid converts it into n-propyl iodide.
If a solution of sodium thiosulphate (hyposulphite) is added to this solution, hydriodic acid, sodium iodide and tetrathionate are formed; and if a little starch solution has been added, the end of the reaction is indicated by the disappearance of the blue colour, due to the iodide of starch.
If some of the anions, instead of being simple iodine ions represented chemically by the symbol I, are complex structures formed by the union of iodine with unaltered cadmium iodide - structures represented by some such chemical formula as I(CdI 2), the concentration of the solution round the anode would be increased by the passage of an electric current, and the phenomena observed would be explained.
If this contained potassium iodide, after coating it could be sensitized with silver nitrate.
In chronic rheumatism the chief remedies are salicylate of soda, and its allies iodide of potassium, guaiacum and sulphur, while massage, liniments and baths are beneficial as local applications.
In each of a number of experiments he found that the weight of the silver iodide did not differ by one twenty-thousandth of the whole from the sum of the weights of the silver and the iodine used.
In many cases, as in syphilis, aneurism, lead poisoning, &c., the life of the patient depends on the free and continued use of the iodide, and this is best to be accomplished by securing an absolutely pure supply of the salt.
In medicine it is frequently employed as a hydragogue purgative, specially valuable in febrile diseases, in congestion of the portal system, and in the obstinate constipation of painters' colic. In the last case it is combined with potassium iodide, the two salts being exceedingly effective in causing the elimination of lead from the system.
In some respects there is a very marked difference between fluorine and the other members of the group, for, whilst sodium chloride, bromide and iodide are readily soluble in water, sodium fluoride is much less soluble; again, silver chloride, bromide and iodide are practically insoluble in water, whilst, on the other hand, silver fluoride is appreciably soluble in water.
In the "diffusion column" method, a liquid column uniformly varying in density from about 3.3 to I is prepared by pouring a little methylene iodide into a long test tube and adding five times as much benzene.
In the case of iodine, the substitution is effected by adding a warm solution of potassium iodide to the diazonium solution, no copper or cuprous salt being necessary; whilst for the production of nitriles a solution of potassium cuprous cyanide is used.
Iodine may also be prepared by the decomposition of an iodide with chlorine, or by heating a mixture of an iodide and manganese dioxide with concentrated sulphuric acid.
It acts as an oxidizing agent, liberating iodine from potassium iodide, converting alcohol into acetaldehyde, &c.
It can be estimated quantitatively by mixing a dilute solution with potassium iodide and hydrochloric acid in excess, adding excess of zinc sulphate, neutralizing the excess of free acid with sodium bicarbonate, and determining the amount of free iodine by a standard solution of sodium thiosulphate.
It does not liberate iodine from potassium iodide, neither does it decolorize iodine solution.
It fumes in air; with water it gives ZrOI 2.8H 2 0; and with alcohol ethyl iodide and zirconium hydroxide are formed.
It is a mercuric iodide in an excess of potassic iodide.
It is also produced by the action of sodium on a mixture of epichlorhydrin and methyl iodide, C 3 H S OC1+CH 3 I+2Na= C 3 H 4 0+NaI+NaC1+CH 4.
It is obtained as a light yellow powder by dissolving the metal in hydriodic acid, or by precipitating a silver salt with a soluble iodide.
It is remarkable that a great many polymorphous substances assume more symmetrical forms at higher temperatures, and a possible explanation of the increase in density of such compounds as silver iodide, &c., may be sought for in the theory that the formation of a more symmetrical configuration would involve a drawing together of the molecules, and consequently an increase in density.
It is very slightly soluble in acids and ammonia, and almost insoluble in alkaline chlorides; potassium iodide, however, dissolves it to form AgI KI.
It may also be prepared by heating tetra-bromor tetra-chlorpyrrol with potas= sium iodide in alcoholic solution (German patent, 38423, 1886).
It may be obtained synthetically by the action of ammonium iodide on cyanamide, CN NH2+ NH 4 I=CN 3 H 5 HI
It was verified very exactly by Stas's experiments, in which he removed the oxygen from the ternary compound silver iodate and found that the whole of the silver and the iodine remained in combination with each other as silver iodide; his results prove, to one part in ten millions, that the combining ratio of the silver and the iodine is unaltered by the removal of the oxygen.
Its aqueous solution gradually decomposes with evolution of oxygen, behaves as a strong oxidant, and liberates iodine from potassium iodide.
Its derivatives and its relation to benzene had been previously studied by the above and other experimenters, its relation to benzene being first proved experimentally by Cannizzaro and its constitution settled by Fittig and Tollens's synthesis from sodium and a mixture of methyl iodide and brombenzene.
Its solution liberates chlorine from hydrochloric acid and iodine from potassium iodide.
Lead bromide, PbBr 2, a white solid, and lead iodide, PbI 21 a yellow solid, are prepared by precipitating a lead salt with a soluble bromide or iodide; they resemble the chloride in solubility.
Long-continued treatment with halogens may, in some cases, result in the formation of aromatic compounds; thus perchlorbenzene, C 6 C1 6, frequently appears as a product of exhaustive chlorination, while hexyl iodide, C 6 H 13 I, yields perchlorand perbrom-benzene quite readily.
Look at the way the solubility products vary from silver chloride to silver iodide.
Mercuric iodide also exhibits dimorphism.
Methylene iodide, CH 2 I 2, has a density of 3.33, and may be diluted with benzene.
Narceine, C23H27N08, obtained by the action of potash on the methyl iodide of narcotine, is probably IV.
Next 5 cc. of glacial acetic acid are added, the solution cooled, and 5 cc. of a solution of potassium iodide (300 grammes to the litre) and the standard solution of sodium thiosulphate run in from a burette until the brown colour has nearly disappeared.
On the outskirts are the Oresund Park, gardens containing iodide and bromide springs, and frequented sea-baths.
Para-xylene is obtained when camphor is distilled with zinc chloride, but it is best prepared from para-brom-toluene or dibrombenzene, methyl iodide and sodium.
Potassium iodide, KI, is obtained by dissolving iodine in potash, the deoxidation of the iodate being facilitated by the addition of charcoal before ignition, proceeding as with the bromide.
Pour a quantity (say 1 oz.) of collodion into a bottle containing dry iodide of silver.
Pyrrol is readily converted into pyridine derivatives by acting with bromoform, chloroform, or methylene iodide on its potassium salt, t3-brom-and O-chlorpyridine being obtained with the first two compounds, and pyridine itself with the last.
Recent work has shown it is too feeble to be relied upon alone, but where really efficient antiseptics, such as mercuric chloride and iodide, and carbolic acid, have been already employed, boracic acid (which, unlike these, is non-poisonous and non-irritant) may legitimately be used to maintain the aseptic or non-bacterial condition which they have obtained.
Silver iodide, mercurous iodide, and mercuric iodide are insoluble in water; lead iodide is sparingly soluble, whilst most of the other metallic iodides are soluble.
Silver picrate and methyl iodide yield the methyl ester, which gives with ammonia picramide.
Small quantities of the iodate (KIO 3) are a frequent impurity in iodide of potassium, and cause the congeries of symptoms known as iodism.
Stannic iodide, Sn14, forms red octahedra and is prepared similarly to stannic bromide.
Stannous iodide, Sn12, forms yellow red needles, and is obtained from potassium iodide and stannous chloride.
Stas recommends solution of the iodine in potassium iodide and subsequent precipitation by the addition of a large excess of water, the precipitate being washed, distilled in steam, and dried in vacuo over solid calcium nitrate, and then over solid caustic baryta.
Stas, from the analysis of pure silver iodate, and by C. Marignac from the determinations of the ratios of silver to iodine, and of silver iodide to iodine; the mean value obtained for the atomic weight being 126.53.
Stas, in his syntheses of silver iodide, weighed the silver and the iodine separately, and after converting them into the compound he weighed this also.
Strychnine is incompatible with liquor arsenicalis and potassium iodide.
Suppose, for instance, the paper ribbon to be soaked in a solution of iodide of potassium and a light contact spring made to press continuously on its surface as it is pulled forward by the mechanism.
Tetramethylammonium iodide, N(CH 3) 4 I, is the chief product obtained by the action of methyl iodide on ammonia (Hofmann).
Thallous iodide, T11, is obtained as a yellow precipitate, which requires 16,000 parts of cold water for its solution, by the addition of potassium iodide to a solution of a thallous salt, or by the direct union of its components.
That's equally true for hydrogen fluoride or hydrogen iodide.
The acid cannot be prepared by the action of concentrated sulphuric acid on an iodide on account of secondary reactions taking place, which result in the formation of free iodine and sulphur dioxide.
The action of potassium bromide and potassium iodide has been treated under bromine and iodine (q.v.).
The alcohol is first acted upon with phosphorus and iodine, and the resulting alkyl iodide is treated with silver nitrite, which gives the corresponding nitroalkyl.
The alkyl derivatives may be obtained by heating phenol with one molecular proportion of a caustic alkali and of an alkyl iodide.
The amount of methyl alcohol present in wood spirit is determined by converting it into methyl iodide by acting with phosphorus iodide; and the acetone by converting it into iodoform by boiling with an alkaline solution of iodine in potassium iodide; ethyl alcohol is detected by giving acetylene on heating with concentrated sulphuric acid, methyl alcohol, !under the same circumstances, giving methyl ether.
The atomic weight of antimony has been determined by the analysis of the chloride, bromide and iodide.
The bromide and iodide are formed in a similar manner by heating the metal in gaseous hydrobromic or hydriodic acids.
The bromide and iodide of nickel resemble the chloride and are prepared in a similar fashion.
The bromide MnBr2.4H20, iodide, Mn12, and fluoride, MnF2, are known.
The bromide, CsBr, and iodide, CsI, resemble the corresponding potassium salts.
The chloride,CdC1 2, bromide,CdBr 2, and iodide,Cdl2,arealsoknown, cadmium iodide being sometimes used in photography, as it is one of the few iodides which are soluble in alcohol.
The chlorine is not completely precipitated by silver nitrate in nitric acid solution, the ionization apparently not proceeding to all the chlorine atoms. Thallic iodide, T11 3, is interesting on account of its isomorphism with rubidium and caesium tri-iodides, a resemblance which suggests the formula T11 (12) for the salt, in which the metal is obviously monovalent.
The combination, as it is ordinarily termed, of chlorine with hydrogen, and the displacement of iodine in potassium iodide by the action of chlorine, may be cited as examples; if these reactions are represented, as such reactions very commonly are, by equations which merely express the relative weights of the bodies which enter into reaction, and of the products, thus Cl = HC1 Hydrogen.
The corresponding iodides are obtained by the addition of potassium iodide to solutions of the sulphonates, and are optically active antipodes.
The difference between amyl iodide and amyl bromide is not sufficiently marked to be of any value."
The fluoride is found native as sellaIte, and the bromide and iodide occur in sea water and in many mineral springs.
The halogens may be sometimes detected by fusing with lime, and testing the solution for a bromide, chloride and iodide in the usual way.
The iodide combines with liquid ammonia to form ZrI 4.8NH 3 i and with ether to give Zr14.4(C2H5)20.
The iodide, Co12, is produced by heating cobalt and iodine together, and forms a greyish-green mass which dissolves readily in water forming a red solution.
The mixture of the iodide and phosphoric(V) acid produces hydrogen iodide which reacts with the alcohol.
The most commonly used salt is the iodide of potassium; the iodides of sodium and ammonium are almost as frequently employed, and those of calcium and strontium are in occasional use.
The most important of the former is the gumm y of tertiary syphilis; this may steadily and completely disappear under the influence of iodide of potassium.
The oxidation, which is effected by chromic acid and sulphuric acid, is conducted in a flask provided with a funnel and escape tube, and the carbon dioxide formed is swept by a current of dry air, previously freed from carbon dioxide, through a drying tube to a set of potash bulbs and a tube containing soda-lime; if halogens are present, a small wash bottle containing potassium iodide, and a U tube containing glass wool moistened with silver nitrate on one side and strong sulphuric acid on the other, must be inserted between the flask and the drying tube.
The same methyl iodide gave with potassium cyanide, acetonitril, which was hydrolysed to acetic acid; this must be C(Coch) a H b H c H d.
The seeding is carried out using silver iodide either from aircraft or, more cost-effectively, ground generators.
The silver iodide is separated and the solvent distilled off.
The soluble iodides, on the addition of silver nitrate to their nitric acid solution, give a yellow precipitate of silver iodide, which is insoluble in ammonia solution.
The stibonium iodide on treatment with moist silver oxide gives the corresponding tetramethyl stibonium hydroxide, Sb(CH 3)40H, which forms deliquescent crystals, of alkaline reaction, and absorbs carbon dioxide readily.
The term allotropy has also been applied to inorganic compounds, identical in composition, but assuming different crystallographic forms. Mercuric oxide, sulphide and iodide; arsenic trioxide; titanium dioxide and silicon dioxide may be cited as examples.
The tertiary amines possess the power of combining with one molecular proportion of an alkyl iodide to form quaternary ammonium salts.
The tertiary arsines, such as As(CH3)3, trimethyl arsine, and the quaternary arsonium iodides and hydroxides, (CH3)4AsI and (CH3)4AsOH, tetramethyl arsonium iodide and hydroxide, have been obtained.
The third most valuable indication which molecular structure gives about these isomers is how to prepare them, for instance, that normal hexane, represented by CH 3 CH 2 CH 2 CH 2 CH 2 CH3, may be obtained by action of sodium on propyl iodide, CH 3 CH 2 CH 2 I, the atoms of iodine being removed from two molecules of propyl iodide, with the resulting fusion.
The valuation of pyrolusite is generally carried out by means of a distillation with hydrochloric acid, the liberated chlorine passing through a solution of potassium iodide, and the amount of iodine liberated being ascertained by means of a standard solution of sodium thiosulphate.
There will also be red colors where the iodine comes into contact with the solid iodide.
They are decomposed on heating, with liberation of oxygen, in some cases leaving a residue of iodide and in others a residue of oxide of the metal, with liberation of iodine as well as of oxygen.
This acid may also be prepared by the electrolysis of concentrated sulphuric acid, and it is distinguishable from persulphuric acid by the fact that it immediately liberates iodine from potassium iodide.
Thus the equation Cl 2 -1-2KI, Aq=2KC1, Aq+12+52400 cal., or (C12) +2KI, Aq =2KC1, Aq+[12]-I-52400 cal., would express that when gaseous chlorine acts on a solution of potassium iodide, with separation of solid iodine, 52400 calories are evolved.
Thymol iodide, official in the United States, is a compound of iodine and thymol; it is also known as aristol or annidalin.
Uranous bromide, UBr4, and uranous iodide, U14, also exist.
We covered up the cell and left the reaction to run overnight to get the best yield of silver iodide possible.
When methyl iodide is used, nitromethane is the sole product, but the higher homologues give more or less of the isomeric nitrous esters.
Whereas calcium chloride, bromide, and iodide are deliquescent solids, the fluoride is practically insoluble in water; this is a parallelism to the soluble silver fluoride, and the insoluble chloride, bromide and iodide.
With iodine it reacts to form nitrogen iodide.
With potassium iodide, glycerin and water, it forms the preparation spirone, which has been used as a spray inhalation in paroxysmal sneezing and asthma.
Zinc bromide, ZnBr 2, and Zinc iodide, Zn12, are deliquescent solids formed by the direct union of their elements.
Zirconium iodide, Zr14, was obtained as a yellow, microcrystalline solid by acting with hydriodic acid on heated zirconium (Wedekind, Ber., 1904, 37, p. 1135).