Polonium, liquid

There are two procedures for doing this. The first makes use of a metal probe coated with an emitter such as polonium or Am (around 1 mCi) and placed above the surface. The resulting air ionization makes the gap between the probe and the liquid sufficiently conducting that the potential difference can be measured by means of a high-impedance dc voltmeter that serves as a null indicator in a standard potentiometer circuit. A submerged reference electrode may be a silver-silver chloride electrode. One generally compares the potential of the film-covered surface with that of the film-free one [83, 84]. 

Metallic polonium has been prepared from polonium hydroxide and some other polonium compounds in the presence of concentrated aqueous or anhydrous liquid ammonia. Two allotropic modifications are known to exist. 

Liquid tellurium boils at 990 °C to a golden yellow vapor, with density that corresponds to the molecular formula T 2- Likewise, in polonium vapor only P02 species are present. Clearly, the decreasing complexity of the solid state of the three elements Se, Te, and Po, as compared to sulfur, is reflected in the vapor state. 

The liquid mine wastes are mainly represented by underground drainage waters (up to 2000 m3/day and even more), as well as low radioactive waste water from uranium treatment plants (from 100 up to 300 m3/day). The uranium isotopes, radium-226, thorium-230, polonium-210, lead-210 are the most dangerous. Their total activity in waste waters reaches often 10-50 Bq/L at the MPC values for natural waters of 0.111 Bq/L. 

Polonium tetrachloride is a bright yellow solid it melts in chlorine at about 300°C 6, 74) to a straw-colored liquid which becomes scarlet at 350°C, possibly through decomposition to the dichloride. It boils at 390°C to give a purple-brown vapor which becomes blue-green above 500°C 6). The reason for this reversible color change is unknown. 

Its solutions in dilute hydrobromic acid are a carmine-red (0.025 M PoBr4) and in more dilute solution (10 3 M), orange red. The tetrabromide is soluble in ethanol, acetone and some other ketones, and is sparingly soluble in liquid bromine. It is hygroscopic and is easily hydrolyzed to a white, basic bromide of variable composition. It forms a yellow ammine in ammonia gas and this yields polonium dibromide and polonium metal on standing, presumably because of radiation decomposition of the ammonia and subsequent hydrogen reduction of the tetrabromide (7). 

Polonium tetranitrate, with at least one molecule of dinitrogen tetroxide of crystallization, is formed as a white crystalline solid by the action of liquid dinitrogen tetroxide on polonium dioxide or tetrachloride polonium metal does not react with this reagent or with its solution in ethyl acetate. The dinitrogen tetroxide is rapidly lost on standing and the resulting tetranitrate decomposes to the basic salt (1) in l i 2 hr. under vacuum (16). 

The air electrode consists of an insulated metal wire with its tip 1-2 mm above the liquid surface and with polonium deposited on the tip to make the air gap conducting. 

First the pitchblende was sifted. (11) Then it was ground. (12) Marie boiled it in a big iron pot, stirring for hours with an iron rod. (13) The liquid was thrown away. (14) Pierre would take what was left and treat it with different chemicals. (15) This helped him know which elements he wanted to throw away and which he wanted to study. (16) Between Marie and Pierre, they found them. (17) The first they named polonium in honor of Poland. (18) It is located in eastern Europe. (19) The second one they called radium. 

The deposition of polonium on metal wires gives rise to a useful a-source. Tips of metal wires having a length 10 mm and a diameter of 0.2 mm were utilized. They were made of Al, Ni, Pd, Pt or An. Each was immersed in 100 pi of a solution containing °Po (300 Bqml ) for 15 h at 27°. Alpha particle emission was measured using a liquid scintillation system. There was an observed diminution in the a-pulse spectra for all of the wires except Al. This was attributed to the mutual diffusion between the wire metal and °Po. The °Po deposited on the Al wire had a tendency to be eluted with the liquid scintillator. This was attributed to physical absorption on the porous metal oxide layer on the Al wire and °Po. The °Po deposited by the Al wire had a tendency to be eluted with the liquid scintillator. It was possible to prepare a °Po -Al wire as a useful a-source by heating at 120° for 30 minutes. 

This method has been extensively used by Schulman and Rided and is indicated diagrammatically in Fig. 47. A small amount of radioactive material, commonly polonium, is mounted on or near the electrode. The a-particle radiation ionises the air between the electrode and the liquid, making it conducting. An electrometer can then be used to measure the potential difference across the gap. Normally, the potential difference is balanced against a standard cell with a potentiometer to obtain a null reading. The electrode E is usually silver-silver chloride, although others have been tried. The main requirement is freedom from appreciable drift during the duration of the experiment. There are references in the literature to the preparation of radioactive sources, but they are now readily available commercially. 

Direct measurements of emerging gamma rays typically use the gamma rays from lead-210 and rely on decays occurring in lung or bone tissues. This method utilizes a system of either sodium iodide or germanium detectors placed over the body in a well-shielded room (Crawford-Brown and Michel 1987). For past exposures, the lead-210 and polonium-210 concentrations in the urine are determined by counting the number of decays on a sodium iodide system or by use of liquid scintillation. 

As only small absolute amounts of radionuclides are to be determined, and thus only small amounts of elements are to be separated, separation cannot usually be properly performed by methods whose success depends on the amount of the component to be isolated (e.g., as in precipitation). Therefore, methods that are independent of amount (such as liquid-liquid extraction and ion-exchange methods) are more advantageous. Extraction procedures very often take advantage of additions of chelating components. For separating volatile radionuclides (such as iodine or ruthenium) from the sample matrix, distillation methods can be used advantageously. Electrolytic deposition has been shown to be applicable in the separation of polonium. 

Curie discover the elements radium and polonium. Marie Curie coins the term radioactivity after her study of these elements. Scottish chemist William Ramsay and English chemist Morris William Travers discover the elements krypton, neon, and xenon. Scottish chemist Sir James Dewar produces liquid hydrogen. 

XIX-3] PANKRATOV, D.V., YEFIMOV, YE.L, TOSHINSKY, GI, RYABAYA L.D., Analysis of polonium hazard in nuclear power installations with lead-bismuth coolant, CD-ROM, Russian Scientific and Technical Forum. Fast Neutron Reactors (To commemorate the 100 birthday of A. I. Leypunsky). Heavy Liquid Metal Coolants in the Nuclear Technologies HLMC-2003 (Proc. of Conf. Obninsk, Russia, December 11-12, 2003) Paper 2401. 

Rutherfordium (Z = 104) cannot be produced directly in " Ca-induced reactions, as it would require a polonium target. The isotopes Rf (Jin. — 160 s) and Rf Ty2 — 1.3 h) are the terminating SF activities of the decay chains derived from and Fl, produced in " Pu(" Ca,xn) reactions with x = 5 and X = 3, respectively [8, 316, 353]. Rf activities produced in hot-fusion reactions with lighter heavy ions with much higher cross sections are generally more appropriate for radiochemical experiments (see Liquid-Phase Chemistry of Superheavy Elements and Gas-Phase Chemistry of Superheavy Elements ). However, the long half-life of Rf may provide the means for previously unexplored radiochemical investigations. 

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