Polonium carbonates

THORIUM AND POLONIUM AS TRACERS FOR ORGANIC CARBON CYCLING IN THE OCEANS... 

Polonium Polonium elecrodeposited from water onto carbon rod, Autoplating - [901,902]... 

Tsunogai and Nozaki [6] analysed Pacific Oceans surface water by consecutive coprecipitations of polonium with calcium carbonate and bismuth oxychloride after addition of lead and bismuth carriers to acidified seawater samples. After concentration, polonium was spontaneously deposited onto silver planchets. Quantitative recoveries of polonium were assumed at the extraction steps and plating step. Shannon et al. [7], who analysed surface water from the Atlantic Ocean near the tip of South Africa, extracted polonium from acidified samples as the ammonium pyrrolidine dithiocarbamate complex into methyl isobutyl ketone. They also autoplated polonium onto silver counting disks. An average efficiency of 92% was assigned to their procedure after calibration with 210Po-210Pb tracer experiments. 

Cowen et al. [5] showed that polonium can be electrodeposited onto carbon rods directly from acidified seawater, stripped from the rods and auto-plated onto silver counting disks with an overall recovery of tracer of 85 4% for an electrodeposition time of 16 h [ 13]. 

Electrodeposition of polonium directly from acidified seawater onto carbon rods. 

Cigarette smoke contains a minute amount of polonium, along with many other carcinogenic chemicals, many of which can cause lung cancer. Over one hundred trace elements and compounds have been identified in cigarette smoke besides polonium. Some examples are nicotine, cresol, carbon monoxide, pyridine, and the carcinogenic compound benzopyrene. 

Polonium may be purified by various processes. Such purification methods include precipitation of polonium as sulfide and then decomposing the sulfide at elevated temperatures spontaneous decomposition of polonium onto a nickel or copper surface and electrolysis of nitric acid solutions of polonium-bismuth mixture. In electrolytic purification polonium is electrodeposited onto a platinum, gold, nickel, or carbon electrode. 

Platinum Dichloride Platinum Dioxide Platinum Hexafluoride Platinum Monoxide Platinum Tetrachloride Plutonium Polonium Potassium Potassium Acetate Potassium Bicarbonate Potassium Bisulfide Potassium Borohydride Potassium Bromate Potassium Bromide Potassium Carbonate... 

The compound is produced by evaporating hydrochloric acid solutions of polonium (IV) 6, 26, 74), by heating the dioxide in carbon tetrachloride vapor 74), in hydrogen chloride, thionyl chloride or with phosphorus pentachloride 6) and by heating the metal in dry chlorine at 200°C (6, 25, 74). It is hygroscopic and hydrolyzes in moist air to a white solid, possibly a basic chloride (7)). The tetrachloride is soluble in thionyl chloride and in water with hydrolysis, and is moderately soluble in ethanol, acetone, and... 

Polonium tetraiodide (8) is a black solid which sublimes in nitrogen at 200°C with partial decomposition to the metal. It is formed from the elements at 40°C/1 mm, by treating polonium dioxide or hydroxide with 0.1 N hydriodic acid, and is precipitated from solutions of polonium(lV) in dilute hydrochloric acid on the addition of 0.1 N hydriodic acid. It is also obtained as a black sublimate by heating polonium dioxide in hydrogen iodide at 200°C a black addition compound (PoCVxHI) is formed in the cold. Polonium metal does not react with iodine dissolved in carbon tetrachloride, but with iodine dissolved in benzene it does react to some extent. 

Polonium dichloride reacts with bromine vapor at, room temperature to give salmon pink PoCUBra. Neither polonium dichloride nor the dibromide reacts with iodine vapor on heating, but both may form unstable interhalogen compounds on treatment with iodine in carbon tetrachloride (7, 8). 

Long treatment of polonium(IV) hydroxide with water saturated with carbon dioxide yields an unstable white solid, apparently a carbonate (12). 

The solubility of "oxidized polonium—probably the dioxide—in aqueous sodium carbonate is about 0.3 mg (of Po210)/liter and does not change appreciably with the carbonate concentration. However, the solubility in aqueous ammonium carbonate increases from 0.089 mg (of Po210)/ liter in 0.25 M solution to 5.2 mg/liter in 0.75 M solution (104, P- 53). 

Both polonium derivatives are chemically very stable, requiring hot fuming nitric acid for their decomposition. However, they char rapidly under the intense alpha bombardment and attempted analyses with acetyl-acetone labeled with carbon-14 in the 1 and 3 positions were unsuccessful. It is interesting that the corresponding yellow oxide, prepared by treating (VI) with aqueous hydrogen peroxide, reverts to (VI) on treatment with aqueous alkali (12). 

In the fourth group, carbon and silicon are both non-metallic, while germanium has a very small electrical conductivity. It is only with white tin and lead that the electrical conductivity approaches the normal values for true metals. In the fifth group, arsenic and antimony are just on the limit between metallic and non-metallic properties, while of the elements of the sixth group, only polonium might be considered to have real metallic properties. The halogens, in the seventh group, show no trace of metallic properties. 

The poor metals among the BCNOs usually include aluminum, gallium, indium, thallium, tin, lead, and bismuth. The metalloids are boron, silicon, germanium, arsenic, antimony, tellurium, and polonium. The nonmetals are carbon, nitrogen, oxygen, phosphorus, sulfur and selenium. These groups are not official, and chemists sometimes disagree on whether a particular element like boron should be called a metal or a metalloid. 

Gold Iridium Platinum Rhodium Ruthenium Palladium Mercury Silver Osmium Selenium Tellurium Polonium Copper Technetium Bismuth Antimony Arsenic Carbon Lead Rhenium Nickel Cobalt... 

One method of preparation of Ar2PoCl2 is described in which At2Po is chlorinated by SO2CI2 in carbon tetrachloride. The diaryl dihalide is precipitated out of the chloroform solution by the addition of petroleum ether. In this manner, the preparation of Ar2PoCl2 has been reported in which Ar is jo-anisyl, mesityl, and a-naphthyl. The bis(o -naphthyl)polonium dichloride can be recrystallized from jo-xylene. 

Internally deposited naturally occurring radionuclides also contribute to the natural radiation dose from inhalation and ingestion of these materials when contained in air, food, and water. Included are radionuclides of lead, polonium, bismuth, radium, potassium, carbon, hydrogen, uranium, and thorium. Potassium-40 is the most prominent radionuclide in normal foods and human tissues. The dose to the total body from these internally deposited radionuclides has been estimated to be 39mremyear. ... 

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