Iridium

“ So with iridium and rhodium, and osmium and ruthenium, which are so closely allied that they make pairs, being separated each from its own group. Then these metals are the most infusible that we possess. Osmium is the most difficult to fuse: indeed, I believe it never has been fused, while every other metal has. Ruthenium comes next, iridium next, rhodium next, platinum next (so that it ranks here as a pretty fusible metal, and yet we have been long accustomed to speak of the infusibility of platinum) , and next comes palladium, which is the most fusible metal of the whole. ”

“ In its pure state it is not acted upon by any of the acids, but it is oxidised by fusion and nitre, and by ignition to redness in the air. An ingot of iridium, weighing 273⁄4 oz., melted by Deville’s process, was displayed in Messrs Johnson and Matthey’s case at the International Exhibition of 1862. An alloy of iridium and osmium (artificial or native) has been employed for tipping the nibs of gold pens (everlasting pens) . ”

“ The precipitate, containing a small quantity of iridium, is then heated with sodium carbonate in a crucible, when the mass decomposes, giving metallic platinum and iridium oxide. If potassium chloride has been employed, the residue after ignition is washed with water and treated with aqua regia. The iridium oxide remains undissolved, and the platinum easily passes into solution. Only cold and dilute aqua regia must be used. The solution will then contain pure platinic chloride, which forms the starting-point for the preparation of all platinum compounds. ”

“ Monoxide, IrO, prepared by adding potassium hydrate to the hexachloride of iridium, and digesting the precipitate in an acid. It is a heavy black powder, insoluble in acid. Sesquioxide, Ir2O3, is best prepared by fusing in a silver crucible a mixture of carbonate of potassium and the double chloride of iridium and potassium, and boiling the product in water. Bluish-black TRIOXIDE, IrO3, is produced when carbonate of potassium is gently heated with hexachloride of iridium. ”

“ IRIDIUM (symbol Ir.; atomic weight 193.1) , one of the metals of the platinum group, discovered in 1802 by Smithson Tennant during the examination of the residue left when platinum ores are dissolved in aqua regia; the element occurs in platinum ores in the form of alloys of platinum and iridium, and of osmium and iridium. Many methods have been devised for the separation of these metals (see Platinum) , one of the best being that of H. St. ”

“ The residue is ignited in a crucible, boiled with water, and dried; it then consists of a mixture of sesquioxide of iron and a combination of oxide of iridium with sodium hydrate. It is reduced by hydrogen at a high temperature, and treated successively with water and strong hydrochloric acid, which remove the alkali and the iron, leaving metallic iridium in a divided state. By strong pressure and exposure to a welding heat, a certain degree of compactness may be given to the product.
Prop., &c. Brittle, white, very hard, only fusible by the strongest heat of Deville’s gas furnace. ”

“ The double chloride is fused with nitre, the melt extracted with water and the residue fused with lead, the excess of lead being finally removed by solution in nitric acid and aqua regia. It is a brittle metal of specific gravity 22.4 (Deville and Debray) , and is only fusible with great difficulty. 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. ”

“ Holland, seeking larger pieces of iridium than could be found in Nature, discovered, after many experiments, that by heating it to a white heat and adding phosphorus, with a few minutes more of heating, he could obtain a perfect fusion, and could pour out the molten metal and get a casting of it. ”

“ But we are near my laboratory now, Dave, and I want to introduce you to Wright, my laboratory assistant, a brilliant student, and an uncannily clever artisan. He made Bartholemew, as I call the mathematics machine, and most of the parts of this ship. He had heat rays to work with, and had iridium metal as his material, and plenty of any element. He had a fine time working out the best alloy, and the best treatment. The shell of the car is made of an alloy of tungsten, iridium and cobalt. It is exceedingly tough, very strong, and very hard. ”

“ The natural transition from titanium and vanadium to copper and zinc by means of the elements of the iron group is demonstrated by all the properties of these elements, and in exactly the same manner a transition from zirconium, niobium, and molybdenum to silver, cadmium, and indium, through ruthenium, rhodium, and palladium, is in perfect accordance with fact and with the magnitude of the atomic weights, as also is the position of osmium, iridium, and platinum between tantalum and tungsten on the one side, and gold and mercury on the other. ”

“ Of or pertaining to iridium; -- applied specifically to compounds in which iridium has a low valence.

I*rid"i*um (*rd"*m) , n. [NL., fr. L. iris, iridis, the rainbow. So called from the iridescence of some of its solutions. See Iris.] (Chem.) A rare metallic element, of the same group as platinum, which it much resembles, being silver-white, but harder, and brittle, and indifferent to most corrosive agents. With the exception of osmium, it is the heaviest substance known, its specific gravity being 22.4. Symbol Ir. Atomic weight 192.5. ”

“ The six metals: ruthenium, Ru, rhodium, Rh, palladium, Pd, osmium, Os, iridium, Ir, and platinum, Pt, are met with associated together in nature. Platinum always predominates over the others, and hence they are known as the platinum metals. By their chemical character their position in the periodic system is in the eighth group, corresponding with iron, cobalt, and nickel. ”

“ Between the Coppermine and Mackenzie Rivers gold and silver are abundant. Platinum and iridium are also common, and are exported from here to all parts of the world; they are in great demand by chemists and electricians. ”

“ A nitrogenous base C10H9N, extracted from coal-tar naphtha, as an oily liquid. It is a member of the quinoline series, and is probably identical with lepidine.
{ Ir`i*dos"mine (?) , Ir`i*dos"mi*um (?) , } n. [Iridium + osmium.] (Min.) The native compound of iridium and osmium. It is found in flattened metallic grains of extreme hardness, and is often used for pointing gold pens.
I"ris (?) , n.; pl. E. Irises (#) , L. Irides (#) . [L. iris, iridis, the goddess, Gr. &?;, &?;, the rainbow, iris of the eye, the plant Iris. Cf. Orris.] 1. (Class. Myth.) ”

“ But it is permitted to hope that the physicists of the future will do still better than those of to-day; and perhaps we may catch a glimpse of the time when we shall begin to observe that the standard, which is constructed from a heavy metal, namely, iridium-platinum, itself obeys an apparently general law, and little by little loses some particles of its mass by emanation. ”

“ But the spectrum of iron, as here described, consists of bright lines; while those with which it is compared in the sun are dark on a bright background. They can be completely understood if we suppose the vapour arising from intensely heated iron to be present in the atmosphere which surrounds the luminous strata on the sun. This vapour would absorb or stop precisely the same rays as it emits when incandescent, and hence we learn the important fact that iron, no less than sodium, must, in one form or another, be a constituent of the sun. ”

“ Saccharine iodide of iron, Saccharum ferri iodidi, Ferri iodidum saccharatum, L. Iron (in powder) , 1 dr.; water, 5 dr.; iodine, 4 dr.; obtain a solution of iodide of iron, as above, and add to it of sugar of milk (in powder) , 11⁄4 oz.; evaporate at a temperature not exceeding 122° Fahr., until the mass has a tenacious consistence, then further add of sugar of milk, 1 oz., reduce the mixture to powder, and preserve it in a well-stoppered bottle. Every 6 gr. contains 1 gr. of iodide of iron.
From “syrup of iodide of iron” exposed in a shallow vessel, in a warm place, until it crystallises ”

“ When zinc containing indium is dissolved not quite completely in dilute sulphuric or muriatic acid, the whole of the indium originally present in the zinc is left in the black spongy or flocculent residue of undissolved metal, with which every one who has prepared hydrogen gas by means of zinc and acid is so well acquainted. Besides some zinc, this black residue is found to contain lead, cadmium, iron, and arsenic, less frequently copper and thallium, and in some cases, as that of the Freiberg zinc, a small proportion of indium. ”

“ I find the nitrate of lead a very useful salt in iodizing paper. Six grains of the salt to the ounce of water, and tincture of iodine added till a pale yellow, will give additional sensitiveness to iodized paper, if the sheets are floated upon the solution. This will shorten the time in the camera nearly five minutes; but it requires care, as it is apt to solarize.
A weak solution of iodide of iron has also the same effect, and, if blotted off at once, it will not blacken by the use of gallic acid. ”

“ In the sun the most prominent spectrum is iron. We do not infer that the sun is unusually rich in iron; we infer that it is at a comparatively low temperature near 6,000° favourable for the production of the iron spectrum. At one time it was thought that the prominence of hydrogen in Sirius and of metallic elements in the sun indicated an evolution of the elements, hydrogen turning into heavier elements as the star cools from the Sirian to the solar stage. ”

“ Potassium is not the only substance that decomposes water. Everybody is familiar with the fact that iron rusts when placed in water. Now the rusting of iron is a similar phenomenon to the conversion of potassium into potash; they both depend upon the absorption of oxygen. At a red heat, iron decomposes water very rapidly. When steam is made to pass through a long red-hot iron tube it is resolved into its elements. The oxygen unites with the iron to form rust, and the hydrogen is set free. ”

“ Thus the molecule of the red matter of the blood contains, for each atom of iron, 712 atoms of carbon, 1,130 of hydrogen, 214 of nitrogen, 245 of oxygen, and 2 of sulphur, or 2,303 atoms in all. Existing in compounds of so complex composition, iron can be present only in very small proportions to the whole. Though an essential element, there is comparatively but little of it. The whole body of man does not contain more than one part in twenty thousand of it. ”

“ Chemistry teaches us that we may, without producing any disarrangement of the affinities, but by merely setting up molecular disturbance, effect decided changes, as is strikingly shown in the colour of iodide of mercury changing from red to yellow under slight influences of heat, and back again to red by a gentle mechanical disturbance. By a slight change, merely molecular, iron may be made to resemble platinum in its physical properties. [32] An iron wire plunged into nitric acid is attacked by the acid with violence ”

“ The latter salt, under the combined influence of hydrogen and heat, is reduced to metallic iron, which assumes the appearance of a fine black powder. When the experiment is completed the glass vessel is closed, and the iron, thus protected from contact with the air, can be preserved indefinitely; but if it is exposed to the air by breaking off the end of the receptacle (fig. 311) , it ignites immediately, producing a shower of fire of very beautiful effect. Iron thus prepared is known under the name of pyrophoric iron. Iron is acted upon in a very powerful manner by most acids. ”

“ The spectroscope has shown that lithium, so far from occurring in only four or five minerals, is a substance very widely diffused in nature. In the waters of the ocean, in mineral and river waters, in most plants, in wines, tea, coffee, milk, blood, and muscle, this metal has been found. Dr. Roscoe states that the ash of a cigar, when moistened with hydrochloric acid, and held in a platinum wire in the flame of the Bunsen’s burner, at once shows the principal lines of sodium, potassium, calcium, and lithium. ”

“ The Latin name for the metal sodium, however, is natrum, and chemists always write Na when they mean sodium; this is fortunate, because S already stands for the element sulfur. Fe means iron (Latin, ferrum) . But I stands for the [pg 298] element iodine. (The iodine you use when you get scratched is the element iodine dissolved in alcohol.) It is not necessary for you to remember the chemical symbols unless you mean to become a chemist or unless you read a good deal about chemistry. But almost every one knows at least that H means hydrogen, O means oxygen, and C means carbon. ”

“ SEPTARIA OF IRON-STONE. Over some lime works at Walsall in Staffordshire, I observed some years ago a stratum of iron earth about six inches thick, full of very large cavities; these cavities were evidently produced when the material passed from a semifluid state into a solid one; as the frit of the potters, or a mixture of clay and water is liable to crack in drying; which is owing to the further contraction of the internal part, after the crust is become hard. ”

“ In my instructions for printing from collodion negatives, a form of iodized paper was given, which, although very good, is not, I think, equal to the following, which is more easily and quickly prepared, exhibits a saving of the iodide of potassium, and is upon the whole a neater mode.
Take sixty grains of nitrate of silver and sixty grains of iodide of potassium; dissolve each separately in an ounce of distilled water; mix together and stir with a glass rod. The precipitate settling, the fluid is to be poured away ”