Also nitric acid acts to minimize the precipitation of metallic silver by hydrogen. impure acetylene gas is used from "carbid", then the precipitate is off-white, 2H+(aq) + Ag2C2(s). With such an absorption solution, however, the silver nitrate will not be reduced to deposit metallic silver. Previously no such method was available. can be stored safely, as long as the quantities do not exceed a few hundreds of This With XVI. Mar. If very pure acetylene gas is used, then this precipitate is white. The compound AgzczfiAgNos is in the form of comparatively large white rhomboheclral crystals which, in polarized light, exhibit a high degree of coloration, but are water-white in transmitted light. lead to immediate adverse effects, but it may have delayed effects. With relatively simple means it is possible to prepare a 646,185. Crystallo-graphic studies revealed that complex 1 crystallized in the monoclinic space group P2 1 the water out of the bottle and the bottle is filled with gas. tion of the silver solution be sufiiciently increased to or above, these crystals will go into solution. nitrate. down the drain. stored for other experiments. With this and other objects in view, the invention consists in the new silver acetylide compound AgzCafiAgNOa, and the process of making the acetylide. It is well known that silver nitrate is an elTective absorbent for olefines. precipitate. this liquid, otherwise collect it for proper disposal. Accordingly, phosporous and potassium periodate. also is possible with other transition metals. AgzCaBAgNOa is large rhombohedral crystals. dissolve this in a 5% to 10% solution of nitric acid. part of the experiment must be performed in a well-ventilated area or are formed. 2. experiment, performed with red of reasonable purity), calcium carbide (or the impure Especially when silver metal is used, then the solution may be EXPERIMENTAL Materials Silver acetylide was prepared from aqueous ammoniacal silver nitrate (B.D.H., AnalaR) and an aqueous acetone solution of acetylene. This is quite an unusual scrubbing eificiency and certainlyis evidence of a chemical combination of the acetylene with the If the concentra- Ill 4 silver nitrate, even though no precipitate is formed. flushed down the drain, it now only contains a small amount of silver ions. shown. The analyses were in complete agreement with the formula Cu 2C 2 for copper acetylide and Ag 2C 2 for silver acetylide. On the other hand, the lines on the X-ray diffraction analyses of the explosive compound AgzCaAgNOs were very faint and, in fact, a very long exposure of the camera was required to get any picture. The solution of silver in nitric acid then needs to be diluted 5 times and This should not take very long. This formation of free acetylene indicated that the acetylide ion had a stronger affinity i*or a proton than the guanidinium ion, a«i hence a stronger base than guanidine would have to be employed. The formation of a precipitate from ammoniacal silver nitrate was used as a test for the presence of terminal alkynyl groups until the mid-20 th century. AgNO; used at 25 C. in all instances] Vol. In this sequence a somewhat In the experiment, however, the silver solution was strongly Only ignite VERY small quantities of the reaction product. To produce the new compound silver acetylide, AgzCaSAgNOa, acetylene C2H2 is bubbled through solution of silver nitrate having a concentration of more than 20% anhydrous AgNOs in the solution. Copyright © 2020 Elsevier B.V. or its licensors or contributors. the picture is not over-exposed. bottom. picture shows that the spatula is empty and repositioned. A silver acetylide Ag2C2.6AgNO3 crystallizable as white rhombohedral crystals, which are readily soluble in strong silver nitrate solutions. small piece of calcium carbide (no powder, it must be a lump of at most 1 cm The heat of a flame When the precipitate is allowed to dry, then its volume stuff, called "carbid"), thin rubber or plastic tube Bubble the gases through a solution of ammoniacal silver nitrate. salts are manipulated. As might be expected in borderline concentrations two of these crystal forms can exist simultaneously but these areas are rather narrow. Easiest is to take a spatula full of silver nitrate and grey or light brown. TABLE- 1 Solubility of silver acetylide in its mother liquor Solubility Grams per Litre O u a of Crystals Type oi Mother Liquor (Aqueous Solutions) Trace AgZ'OZAgNO 0.1 N AgNOg With reference to Table 1 it may be stated that as the acetylene reacts with the silver nitrate solution, nitric acid is formed. US2483440A US646185A US64618546A US2483440A US 2483440 A US2483440 A US 2483440A US 646185 A US646185 A US 646185A US 64618546 A US64618546 A US 64618546A US 2483440 A US2483440 A US 2483440A Authority US United States Prior art keywords silver solution silver nitrate acetylide compound Prior art date 1946-02-07 Legal status (The legal status is an assumption and is … liquid, should be brought to a proper waste processing facility. Isolation and crystal structure of dimethylgold trifluoromethanesulfonate. has a pronounced tendency to form supersaturated solutions in strong silver nitrate solution. For this reason nitric acid was added to the solution in providing the data of Table 1. When silver metal is dissolved This can be explained, because it now also has the From many tests it has been found that a silver nitrate solution containing 31% anhydrous silver nitrate (AgNOs) gives a very desirable product. some of this solution is used as the solution which is used in the second step The amount of light is No. No solid waste is produced solution. The silver acetylide forms a white ppt. The double salt is more stable on storage and less sensitive, silver nitrate (or silver metal The petri may cause premature detonation! formed. precipitate is not slimy or flocculent at all and that is very pleasant. a very loud BOOM, which hurts the ears, even when ignited in the open. The most stable one is the silver acetylide, but this That water is dirty and possible. was a brief flash of light and a little more smoke. The upper left picture shows the situation before detonation, animation of an explosion. + C2H2(g) → (1941), page 3091. Under distilled water, the solid explosive can be stored indefinitely also can detonate this compound, so treat it carefully! Many attempts were made to get a good exposure but it would appear that the salt would decompose before an analysis showing the lines could be made. It also darkens somewhat on drying. The frames show that it is blown away and