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92-766: The Härmelekopf is a mountain northeast of Seefeld in Tirol in the Karwendel Alps in the Austrian state of Tyrol . It is 2,224 metres high. About 400 metres from the summit of the Härmelekopf is the top station of the Härmelekopfbahn cable car, from where there is a steep and difficult path to the top which then continues along an arête to the Reither Spitze . Another easier path leads from

184-423: A regular octahedral molecule, unlike the distorted octahedral structure of XeF 6 , because of the inert pair effect . Because radon is quite electropositive for a noble gas, it is possible that radon fluorides actually take on highly fluorine-bridged structures and are not volatile. Extrapolation down the noble gas group would suggest also the possible existence of RnO, RnO 2 , and RnOF 4 , as well as

276-403: A Pennsylvania nuclear power plant, a worker was found to be contaminated with radioactivity. A high concentration of radon in his home was subsequently identified as responsible. Discussions of radon concentrations in the environment refer to Rn, the decay product of uranium and radium. While the average rate of production of Rn (from the thorium decay series) is about the same as that of Rn,

368-424: A building directly from the soil through the lowest level in the building that is in contact with the ground. High levels of radon in the water supply can also increase indoor radon air levels. Typical entry points of radon into buildings are cracks in solid foundations and walls, construction joints, gaps in suspended floors and around service pipes, cavities inside walls, and the water supply. Radon concentrations in

460-424: A depth of 15 cm), contains about 1 gram of radium, which releases radon in small amounts to the atmosphere. It is estimated that 2.4 billion curies (90 EBq) of radon are released from soil annually worldwide. This is equivalent to some 15.3 kilograms (34 lb). Radon concentration can differ widely from place to place. In the open air, it ranges from 1 to 100 Bq/m , even less (0.1 Bq/m ) above

552-436: A few tens of grams of radon, consistently replaced by decay of larger amounts of radium, thorium, and uranium. Radon is produced by the radioactive decay of radium-226, which is found in uranium ores, phosphate rock, shales, igneous and metamorphic rocks such as granite, gneiss, and schist, and to a lesser degree, in common rocks such as limestone. Every square mile of surface soil, to a depth of 6 inches (2.6 km to

644-594: A given territory. Thus, the geometric mean is generally used for estimating the "average" radon concentration in an area. The mean concentration ranges from less than 10 Bq/m to over 100 Bq/m in some European countries. Some of the highest radon hazard in the US is found in Iowa and in the Appalachian Mountain areas in southeastern Pennsylvania. Iowa has the highest average radon concentrations in

736-632: A health spring. Its radon content of 117 becquerels per litre is rather low (the limit for drinking water is 1,000 Bq/L). The Klammbach originates at the Wildmoosalm below the lake of Wildmoossee and runs northwest of the village on the far side of the Geigenbühel, passes the Triendlsäge (where there is a reservoir with a capacity of 450 m which supplies a small hydropower station generating 45  kW ) and merges with

828-493: A higher concentration of uranium. Not all granitic regions are prone to high emissions of radon. Being a rare gas, it usually migrates freely through faults and fragmented soils, and may accumulate in caves or water. Owing to its very short half-life (four days for Rn), radon concentration decreases very quickly when the distance from the production area increases. Radon concentration varies greatly with season and atmospheric conditions. For instance, it has been shown to accumulate in

920-494: A low volatility and was thought to be RnF 2 . Because of the short half-life of radon and the radioactivity of its compounds, it has not been possible to study the compound in any detail. Theoretical studies on this molecule predict that it should have a Rn–F bond distance of 2.08  ångströms (Å), and that the compound is thermodynamically more stable and less volatile than its lighter counterpart xenon difluoride ( XeF 2 ). The octahedral molecule RnF 6

1012-507: A measure of radioactivity commonly used in mining). These conditions are not always met; in many homes, the equilibrium factor is typically 40%; that is, there will be 0.004 WL of daughters for each pCi/L of radon in the air. Pb takes much longer to come in equilibrium with radon, dependent on environmental factors, but if the environment permits accumulation of dust over extended periods of time, Pb and its decay products may contribute to overall radiation levels as well. Several studies on

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1104-430: A noble gas and does not adhere to lung tissue (meaning it is often exhaled before decaying), the radon daughters attached to dust are more likely to stick to the lungs. This increases the risk of harm, as the radon daughters can cause damage to lung tissue. Radon and its daughters are, taken together, often the single largest contributor to an individual's background radiation dose, but due to local differences in geology,

1196-700: A radioactive gas he named "radium emanation" ("Ra Em"). In 1901, Rutherford and Harriet Brooks demonstrated that the emanations are radioactive, but credited the Curies for the discovery of the element. In 1903, similar emanations were observed from actinium by André-Louis Debierne , and were called "actinium emanation" ("Ac Em"). Several shortened names were soon suggested for the three emanations: exradio , exthorio , and exactinio in 1904; radon (Ro), thoron (To), and akton or acton (Ao) in 1918; radeon , thoreon , and actineon in 1919, and eventually radon , thoron , and actinon in 1920. (The name radon

1288-527: A step in the normal radioactive decay chain of U, also known as the uranium series , which slowly decays into a variety of radioactive nuclides and eventually decays into stable Pb . Rn occurs in minute quantities as an intermediate step in the decay chain of Th, also known as the thorium series , which eventually decays into stable Pb . Radon was discovered in 1899 by Ernest Rutherford and Robert B. Owens at McGill University in Montreal , and

1380-483: A wasting disease of miners, the mala metallorum , and Georg Agricola recommended ventilation in mines to avoid this mountain sickness ( Bergsucht ). In 1879, this condition was identified as lung cancer by Harting and Hesse in their investigation of miners from Schneeberg, Germany. The first major studies with radon and health occurred in the context of uranium mining in the Joachimsthal region of Bohemia . In

1472-424: Is inert to most common chemical reactions, such as combustion , because the outer valence shell contains eight electrons . This produces a stable, minimum energy configuration in which the outer electrons are tightly bound. Its first ionization energy —the minimum energy required to extract one electron from it—is 1037 kJ/mol. In accordance with periodic trends , radon has a lower electronegativity than

1564-496: Is a colorless, odorless gas, the only way to know how much is present in the air or water is to perform tests. In the US, radon test kits are available to the public at retail stores, such as hardware stores, for home use, and testing is available through licensed professionals, who are often home inspectors . Efforts to reduce indoor radon levels are called radon mitigation . In the US, the EPA recommends all houses be tested for radon. In

1656-581: Is a contaminant that affects indoor air quality worldwide. According to the United States Environmental Protection Agency (EPA), radon is the second most frequent cause of lung cancer, after cigarette smoking, causing 21,000 lung cancer deaths per year in the United States. About 2,900 of these deaths occur among people who have never smoked. While radon is the second most frequent cause of lung cancer, it

1748-571: Is a decay product of Ra , the latter being itself a decay product of U . A trace amount of the (highly unstable) isotope Rn (half-life about 35  milliseconds ) is also among the daughters of Rn. The isotope Rn would be produced by the double beta decay of natural Po; while energetically possible, this process has however never been seen. Three other radon isotopes have a half-life of over an hour: Rn (about 15 hours), Rn (2.4 hours) and Rn (about 1.8 hours). However, none of these three occur naturally. Rn, also called thoron,

1840-472: Is a member of the community Best of the Alps . [REDACTED] Media related to Seefeld in Tirol at Wikimedia Commons Radon Radon is a chemical element ; it has symbol Rn and atomic number 86. It is a radioactive noble gas and is colorless and odorless. Of the three naturally occurring radon isotopes, only Rn has a sufficiently long half-life (3.825 days) for it to be released from

1932-477: Is a natural decay product of the most stable thorium isotope ( Th). It has a half-life of 55.6 seconds and also emits alpha radiation . Similarly, Rn is derived from the most stable isotope of actinium ( Ac)—named "actinon"—and is an alpha emitter with a half-life of 3.96 seconds. Rn belongs to the radium and uranium-238 decay chain, and has a half-life of 3.8235 days. Its first four products (excluding marginal decay schemes ) are very short-lived, meaning that

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2024-467: Is also lowered by air circulation or air filtration devices, and is increased by airborne dust particles, including cigarette smoke. The equilibrium factor found in epidemiological studies is 0.4. Radon was discovered in 1899 by Ernest Rutherford and Robert B. Owens at McGill University in Montreal . It was the fifth radioactive element to be discovered, after uranium, thorium, radium, and polonium. In 1899, Pierre and Marie Curie observed that

2116-643: Is also provided over the cable network. Since August 2012 there has been free WLAN access in the pedestrian zone, the spa park, the sport and congress centre, around the Seekirchl and at the Casino Arena , around the ski jumps on the Gschwandtkopf and at several stations in the Rosshütte ski area . In recent years Seefeld has expanded and renovated its sports facilities and positioned itself as

2208-418: Is expected to be more stable than RnF 6 due to spin–orbit splitting of the 6p shell of radon (Rn would have a closed-shell 6s 6p 1/2 configuration). Therefore, while RnF 4 should have a similar stability to xenon tetrafluoride ( XeF 4 ), RnF 6 would likely be much less stable than xenon hexafluoride ( XeF 6 ): radon hexafluoride would also probably be

2300-530: Is expressed in joule-hours per cubic meter (J·h/m ). One WLM is equivalent to 3.6 × 10 J·h/m . An exposure to 1 WL for 1 working-month (170 hours) equals 1 WLM cumulative exposure. The International Commission on Radiological Protection recommends an annual limit of 4.8WLM for miners. Assuming 2000 hours of work per year, this corresponds to a concentration of 1500  Bq/m . Rn decays to Pb and other radioisotopes. The levels of Pb can be measured. The rate of deposition of this radioisotope

2392-533: Is not related to that of the Austrian mathematician Johann Radon .) The likeness of the spectra of these three gases with those of argon, krypton, and xenon, and their observed chemical inertia led Sir William Ramsay to suggest in 1904 that the "emanations" might contain a new element of the noble-gas family. In 1909, Ramsay and Robert Whytlaw-Gray isolated radon and determined its melting temperature and approximate density . In 1910, they determined that it

2484-485: Is regulated, but it is available in small quantities for the calibration of Rn measurement systems. In 2008 it was priced at almost US$ 6,000 (equivalent to $ 8,491 in 2023) per milliliter of radium solution (which only contains about 15 picograms of actual radon at any given moment). Radon is produced commercially by a solution of radium-226 (half-life of 1,600 years). Radium-226 decays by alpha-particle emission, producing radon that collects over samples of radium-226 at

2576-486: Is seldom performed with radon, and as a result there are very few reported compounds of radon, all either fluorides or oxides . Radon can be oxidized by powerful oxidizing agents such as fluorine , thus forming radon difluoride ( RnF 2 ). It decomposes back to its elements at a temperature of above 523 K (250 °C; 482 °F), and is reduced by water to radon gas and hydrogen fluoride: it may also be reduced back to its elements by hydrogen gas. It has

2668-489: Is small and appropriate for beginners. There are two separate small areas which are not connected except by a ski bus (free of charge) or taxis. The terrain itself is quite good and there is good access to other facilities (walks, shops and the Olympia swimming complex). Seefeld is popular with walkers because of its plateau location; there are many attractive walks which don't depend on climbing up and down mountains. However,

2760-496: Is the absolute temperature, and A {\displaystyle A} and B {\displaystyle B} are solvent constants. Radon is a member of the zero- valence elements that are called noble gases, and is chemically not very reactive . The 3.8-day half-life of Rn makes it useful in physical sciences as a natural tracer . Because radon is a gas at standard conditions, unlike its decay-chain parents, it can readily be extracted from them for research. It

2852-405: Is the number one cause among non-smokers, according to EPA policy-oriented estimates. Significant uncertainties exist for the health effects of low-dose exposures. Radon is a colorless, odorless, and tasteless gas and therefore is not detectable by human senses alone. At standard temperature and pressure , it forms a monatomic gas with a density of 9.73 kg/m , about 8 times the density of

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2944-721: Is threatened by sediment deposition from the Haglbach . In future it is planned to excavate a reservoir east of Innsbrucker Straße to collect these sediments. The tailstream of the Wildsee, now called the Seebach, runs through Seefeld in a northerly direction and collects the waters of the Raabach shortly after passing the village centre. This section was called the Mühlbach by Peter Anich in 1762. The Raabach has its source in

3036-445: Is weather-dependent. Radon concentrations found in natural environments are much too low to be detected by chemical means. A 1,000 Bq/m (relatively high) concentration corresponds to 0.17  picogram per cubic meter (pg/m ). The average concentration of radon in the atmosphere is about 6 × 10 molar percent , or about 150 atoms in each milliliter of air. The radon activity of the entire Earth's atmosphere originates from only

3128-493: The Earth's atmosphere are so low that radon-rich water in contact with the atmosphere will continually lose radon by volatilization . Hence, ground water has a higher concentration of Rn than surface water , because radon is continuously produced by radioactive decay of Ra present in rocks. Likewise, the saturated zone of a soil frequently has a higher radon content than the unsaturated zone because of diffusional losses to

3220-436: The Earth's atmosphere at sea level, 1.217 kg/m . It is one of the densest gases at room temperature (a few are denser, e.g. CF 3 (CF 2 ) 2 CF 3 and WF 6 ) and is the densest of the noble gases. Although colorless at standard temperature and pressure, when cooled below its freezing point of 202 K (−71 °C; −96 °F), it emits a brilliant radioluminescence that turns from yellow to orange-red as

3312-598: The Nordic Competence Centre ( Nordisches Kompetenzzentrum ) for the training of national teams and clubs as well as the Stams Skiing Grammar School ( Skigymnasium Stams ). Seefeld is an important centre for cross-country skiing . The Nordic events at both the 1964 and 1976 Winter Olympics were hosted at Seefeld. Competitions during the 1933 , 1985 and 2019 FIS Nordic Skiing World Championships also took place here. In both

3404-634: The Reiterjoch Alm (the Reiteralmbahn ). Seefeld in Tirol With more than one million overnight stays each year, it is one of the most popular Tyrolean tourist destinations especially for skiing in winter, but also for walking holidays in the summer. To the northwest Seefeld borders on Leutasch (village of Weidach ), to the northeast on Scharnitz (village of Gießenbach). Its eastern municipal boundary with Zirl runs along

3496-863: The Seebach by the Lehenwald woods in front of the Bodenalm to form the Drahnbach . The latter flows towards Scharnitz and empties into the Isar tributary, the Gießenbach . The reservoir at 1,578 m above sea level (AA) near the Rosshütte (called the Kaltwassersee and named after the local area) has a capacity of 66,500 m and receives its water from the public mains. In 2015 it

3588-626: The Wetterstein mountain range to the west, and the Karwendel mountain range to the east; it falls away in a steep drop off to the Inn valley to the south. To the north, the high valley leads through the village of Scharnitz towards the border with Germany at Mittenwald . Seefeld has two main mountain areas (for walking or skiing): one is the rounded hill, the Gschwandtkopf (1,495 m);

3680-538: The inert pair effect . Radon reacts with the liquid halogen fluorides ClF, ClF 3 , ClF 5 , BrF 3 , BrF 5 , and IF 7 to form RnF 2 . In halogen fluoride solution, radon is nonvolatile and exists as the RnF and Rn cations; addition of fluoride anions results in the formation of the complexes RnF 3 and RnF 4 , paralleling the chemistry of beryllium (II) and aluminium (III). The standard electrode potential of

3772-781: The German border is part of the European route E 533. It runs from Zirl over the Zirler Berg to Scharnitz and Mittenwald . Another road link from the Inn valley runs from Telfs via Mösern, along the road to Leutasch and enables Mittenwald to be reached over the Scharnitz Pass . Innsbruck Airport lies about 20 km from Seefeld. In winter there are direct flights from e. g. Hamburg, Berlin, Cologne and Frankfurt. The pilot project by Telesystem Tirol for cable TV

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3864-597: The Pfarrhügel, a spur of the Gschwandtkopf running into the town centre and forming a small attractive hill. There is also a popular bathing lake called the Wildsee . On the east side of the Seefelder Joch rise the tributaries of the Haglbach , which flows west through the valley of Hermannstal , then swings south on reaching the plateau to run along the municipal boundary and feed the Wildsee . The Wildsee

3956-466: The Rn /Rn couple has been estimated as +2.0 V, although there is no evidence for the formation of stable radon ions or compounds in aqueous solution. Radon has no stable isotopes . Thirty-nine radioactive isotopes have been characterized, with mass numbers ranging from 193 to 231. Six of them, from 217 to 222 inclusive, occur naturally. The most stable isotope is Rn (half-life 3.82 days), which

4048-615: The UK, under the Housing Health & Safety Rating System, property owners have an obligation to evaluate potential risks and hazards to health and safety in a residential property. Alpha-radiation monitoring over the long term is a method of testing for radon that is more common in countries outside the United States. Radon is obtained as a by-product of uraniferous ores processing after transferring into 1% solutions of hydrochloric or hydrobromic acids . The gas mixture extracted from

4140-625: The US due to significant glaciation that ground the granitic rocks from the Canadian Shield and deposited it as soils making up the rich Iowa farmland. Many cities within the state, such as Iowa City , have passed requirements for radon-resistant construction in new homes. The second highest readings in Ireland were found in office buildings in the Irish town of Mallow, County Cork , prompting local fears regarding lung cancer. Since radon

4232-463: The US, studies and mitigation only followed decades of health effects on uranium miners of the Southwestern US employed during the early Cold War ; standards were not implemented until 1971. In the early 20th century in the US, gold contaminated with the radon daughter Pb entered the jewelry industry. This was from gold brachytherapy seeds that had held Rn, which were melted down after

4324-513: The United States and Norway aimed to measure radon indoors and in metropolitan areas. High concentrations of radon in homes were discovered by chance in 1984 after the stringent radiation testing conducted at the new Limerick Generating Station nuclear power plant in Montgomery County, Pennsylvania, United States revealed that Stanley Watras , a construction engineer at the plant, was contaminated by radioactive substances even though

4416-726: The Winter Olympics and the 1985 World Championships only the normal hill in ski jumping took place in Seefeld, the large hill took place in Innsbruck ) as well as some of the events at the 1st Winter Youth Olympic Games in January 2012. World Cup competitions have been located here a number of times. During the 2019 World Championships, ski jumping took place in Seefeld in Tirol. The 1963 Biathlon World Championships also took place in Seefeld in Tirol. The alpine skiing area

4508-401: The accepted name for the element's most stable isotope, Rn. Under standard conditions, radon is gaseous and can be easily inhaled, posing a health hazard. However, the primary danger comes not from radon itself, but from its decay products, known as radon daughters. These decay products, often existing as single atoms or ions, can attach themselves to airborne dust particles. Although radon is

4600-569: The air at the (unventilated) Gastein Healing Gallery averages 43 kBq/m (1.2 nCi/L) with maximal value of 160 kBq/m (4.3 nCi/L). Radon mostly appears with the radium/ uranium series (decay chain) ( Rn), and marginally with the thorium series ( Rn). The element emanates naturally from the ground, and some building materials, all over the world, wherever traces of uranium or thorium are found, and particularly in regions with soils containing granite or shale , which have

4692-644: The air if there is a meteorological inversion and little wind. High concentrations of radon can be found in some spring waters and hot springs. The towns of Boulder, Montana ; Misasa ; Bad Kreuznach , Germany; and the country of Japan have radium-rich springs that emit radon. To be classified as a radon mineral water, radon concentration must be above 2 nCi/L (74 kBq/m ). The activity of radon mineral water reaches 2 MBq/m in Merano and 4 MBq/m in Lurisia (Italy). Natural radon concentrations in

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4784-555: The amount of Rn in the environment is much less than that of Rn because of the short half-life of Rn (55 seconds, versus 3.8 days respectively). Radon concentration in the atmosphere is usually measured in becquerel per cubic meter (Bq/m ), the SI derived unit . Another unit of measurement common in the US is picocuries per liter (pCi/L); 1 pCi/L = 37 Bq/m . Typical domestic exposures average about 48 Bq/m indoors, though this varies widely, and 15 Bq/m outdoors. In

4876-535: The arête from the Seefelder Joch and Seefelder Spitze. To the south lies Reith (village of Auland) and to the west Telfs (village of Mösern ). The village is situated on the south-facing Seefeld Plateau north of the River Inn on the watershed between the basins of the Inn and the Isar . The plateau (which also comprises the villages of Leutasch , Reith , Scharnitz and Mösern ) is surrounded by

4968-410: The atmosphere following seismic events leading to earthquakes , which has led to its investigation in the field of earthquake prediction . It is possible to test for radon in buildings, and to use techniques such as sub-slab depressurization for mitigation . Epidemiological studies have shown a clear association between breathing high concentrations of radon and incidence of lung cancer . Radon

5060-696: The atmosphere. In 1971, Apollo 15 passed 110 km (68 mi) above the Aristarchus plateau on the Moon , and detected a significant rise in alpha particles thought to be caused by the decay of Rn. The presence of Rn has been inferred later from data obtained from the Lunar Prospector alpha particle spectrometer. Radon is found in some petroleum . Because radon has a similar pressure and temperature curve to propane , and oil refineries separate petrochemicals based on their boiling points,

5152-488: The concentration of short-lived isotopes will increase until an equilibrium is reached where the overall decay rate of the decay products equals that of the radon itself. The equilibrium factor is 1 when both activities are equal, meaning that the decay products have stayed close to the radon parent long enough for the equilibrium to be reached, within a couple of hours. Under these conditions, each additional pCi/L of radon will increase exposure by 0.01  working level (WL,

5244-422: The corresponding disintegrations are indicative of the initial radon distribution. Its decay goes through the following sequence: The radon equilibrium factor is the ratio between the activity of all short-period radon progenies (which are responsible for most of radon's biological effects), and the activity that would be at equilibrium with the radon parent. If a closed volume is constantly supplied with radon,

5336-403: The decay of radium in radium halides, a reaction that has been used to reduce the amount of radon that escapes from targets during irradiation . Additionally, salts of the [RnF] cation with the anions SbF 6 , TaF 6 , and BiF 6 are known. Radon is also oxidised by dioxygen difluoride to RnF 2 at 173 K (−100 °C; −148 °F). Radon oxides are among

5428-426: The element one period before it, xenon , and is therefore more reactive. Early studies concluded that the stability of radon hydrate should be of the same order as that of the hydrates of chlorine ( Cl 2 ) or sulfur dioxide ( SO 2 ), and significantly higher than the stability of the hydrate of hydrogen sulfide ( H 2 S ). Because of its cost and radioactivity, experimental chemical research

5520-408: The existence of Xe(VIII), no Rn(VIII) compounds have been claimed to exist; RnF 8 should be highly unstable chemically (XeF 8 is thermodynamically unstable). It is predicted that the most stable Rn(VIII) compound would be barium perradonate (Ba 2 RnO 6 ), analogous to barium perxenate . The instability of Rn(VIII) is due to the relativistic stabilization of the 6s shell, also known as

5612-576: The fact that radon levels in particular dwellings can occasionally be orders of magnitude higher than typical. Since the incident in Pennsylvania, millions of short-term radon measurements have been taken in homes in the United States. Outside the United States, radon measurements are typically performed over the long term. In the United States, typical domestic exposures are of approximately 100 Bq/m (2.7 pCi/L) indoors. Some level of radon will be found in all buildings. Radon mostly enters

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5704-563: The few other reported compounds of radon ; only the trioxide ( RnO 3 ) has been confirmed. The higher fluorides RnF 4 and RnF 6 have been claimed and are calculated to be stable, but their identification is unclear. They may have been observed in experiments where unknown radon-containing products distilled together with xenon hexafluoride : these may have been RnF 4 , RnF 6 , or both. Trace-scale heating of radon with xenon, fluorine, bromine pentafluoride , and either sodium fluoride or nickel fluoride

5796-404: The first chemically stable noble gas chlorides RnCl 2 and RnCl 4 , but none of these have yet been found. Radon carbonyl (RnCO) has been predicted to be stable and to have a linear molecular geometry . The molecules Rn 2 and RnXe were found to be significantly stabilized by spin-orbit coupling . Radon caged inside a fullerene has been proposed as a drug for tumors . Despite

5888-474: The formation of RnO 3 , but this could not be confirmed. It is likely that the difficulty in identifying higher fluorides of radon stems from radon being kinetically hindered from being oxidised beyond the divalent state because of the strong ionicity of radon difluoride ( RnF 2 ) and the high positive charge on radon in RnF ; spatial separation of RnF 2 molecules may be necessary to clearly identify higher fluorides of radon, of which RnF 4

5980-557: The gas emitted by radium remained radioactive for a month. Later that year, Rutherford and Owens noticed variations when trying to measure radiation from thorium oxide. Rutherford noticed that the compounds of thorium continuously emit a radioactive gas that remains radioactive for several minutes, and called this gas "emanation" (from Latin : emanare , to flow out, and emanatio , expiration), and later "thorium emanation" ("Th Em"). In 1900, Friedrich Ernst Dorn reported some experiments in which he noticed that radium compounds emanate

6072-640: The hydrolysed solution. That [RnO 3 F] did not form in other experiments may have been due to the high concentration of fluoride used. Electromigration studies also suggest the presence of cationic [HRnO 3 ] and anionic [HRnO 4 ] forms of radon in weakly acidic aqueous solution (pH > 5), the procedure having previously been validated by examination of the homologous xenon trioxide. The decay technique has also been used. Avrorin et al. reported in 1982 that Fr compounds cocrystallised with their caesium analogues appeared to retain chemically bound radon after electron capture; analogies with xenon suggested

6164-469: The inside of pipework. Measurement of radon levels in the first decades of its discovery was mainly done to determine the presence of radium and uranium in geological surveys. In 1956, most likely the first indoor survey of radon decay products was performed in Sweden, with the intent of estimating the public exposure to radon and its decay products. From 1975 up until 1984, small studies in Sweden, Austria,

6256-440: The level of exposure to radon gas differs by location. A common source of environmental radon is uranium-containing minerals in the ground; it therefore accumulates in subterranean areas such as basements. Radon can also occur in ground water, such as spring waters and hot springs. Radon trapped in permafrost may be released by climate-change -induced thawing of permafrosts , and radon may also be released into groundwater and

6348-439: The mining industry, the exposure is traditionally measured in working level (WL), and the cumulative exposure in working level month (WLM); 1 WL equals any combination of short-lived Rn daughters ( Po, Pb, Bi, and Po) in 1 liter of air that releases 1.3 × 10  MeV of potential alpha energy; 1 WL is equivalent to 2.08 × 10 joules per cubic meter of air (J/m ). The SI unit of cumulative exposure

6440-459: The name of the most stable isotope, radon, as the name of the element. The isotopes thoron and actinon were later renamed Rn and Rn. This has caused some confusion in the literature regarding the element's discovery as while Dorn had discovered radon the isotope, he was not the first to discover radon the element. As late as the 1960s, the element was also referred to simply as emanation . The first synthesized compound of radon, radon fluoride,

6532-453: The ocean. In caves or ventilated mines, or poorly ventilated houses, its concentration climbs to 20–2,000 Bq/m . Radon concentration can be much higher in mining contexts. Ventilation regulations instruct to maintain radon concentration in uranium mines under the "working level", with 95th percentile levels ranging up to nearly 3 WL (546 pCi Rn per liter of air; 20.2 kBq/m , measured from 1976 to 1985). The concentration in

6624-468: The other is on the slopes of the mountains to the east and called the Rosshütte after the large mountain restaurant halfway up. These mountains dominate the Seefeld Plateau; from left/north to right/south, they are the Seefelder Joch, Seefelder Spitze (2,215 m), Härmelekopf (2,224 m) and Reither Spitze (2,374 m). Notable other landmarks include the Seekirchl, a small, onion-domed church, and

6716-415: The piping carrying freshly separated propane in oil refineries can become contaminated because of decaying radon and its products. Residues from the petroleum and natural gas industry often contain radium and its daughters. The sulfate scale from an oil well can be radium rich, while the water, oil, and gas from a well often contains radon. Radon decays to form solid radioisotopes that form coatings on

6808-553: The radioactive emanations may contain a new element of the noble gas family, and isolated "radium emanation" in 1909 to determine its properties. In 1911, the element Ramsay and Whytlaw-Gray isolated was accepted by the International Commission for Atomic Weights , and in 1923, the International Committee for Chemical Elements and International Union of Pure and Applied Chemistry chose radon as

6900-452: The radioactive equilibrium of elements in the environment find it more useful to use the ratio of other Rn decay products with Pb, such as Po, in measuring overall radiation levels. Because of their electrostatic charge , radon progenies adhere to surfaces or dust particles, whereas gaseous radon does not. Attachment removes them from the air, usually causing the equilibrium factor in the atmosphere to be less than 1. The equilibrium factor

6992-423: The radon had decayed. The presence of radon in indoor air was documented as early as 1950. Beginning in the 1970s, research was initiated to address sources of indoor radon, determinants of concentration, health effects, and mitigation approaches. In the US, the problem of indoor radon received widespread publicity and intensified investigation after a widely publicized incident in 1984. During routine monitoring at

7084-412: The reactor had never been fueled and Watras had been decontaminated each evening. It was determined that radon levels in his home's basement were in excess of 100,000 Bq/m (2.7 nCi/L); he was told that living in the home was the equivalent of smoking 135 packs of cigarettes a day, and he and his family had increased their risk of developing lung cancer by 13 or 14 percent. The incident dramatized

7176-416: The same place may differ by double/half over one hour, and the concentration in one room of a building may be significantly different from the concentration in an adjoining room. The distribution of radon concentrations will generally differ from room to room, and the readings are averaged according to regulatory protocols. Indoor radon concentration is usually assumed to follow a log-normal distribution on

7268-651: The soil and rock where it is generated. Radon isotopes are the immediate decay products of radium isotopes. The instability of Rn, its most stable isotope, makes radon one of the rarest elements. Radon will be present on Earth for several billion more years despite its short half-life, because it is constantly being produced as a step in the decay chains of U and Th , both of which are abundant radioactive nuclides with half-lives of at least several billion years. The decay of radon produces many other short-lived nuclides , known as "radon daughters", ending at stable isotopes of lead . Rn occurs in significant quantities as

7360-465: The solutions contains H 2 , O 2 , He, Rn, CO 2 , H 2 O and hydrocarbons . The mixture is purified by passing it over copper at 993 K (720 °C; 1,328 °F) to remove the H 2 and the O 2 , and then KOH and P 2 O 5 are used to remove the acids and moisture by sorption . Radon is condensed by liquid nitrogen and purified from residue gases by sublimation . Radon commercialization

7452-806: The southeast near the Mösern Mähder and was once impounded to form a reservoir that gave the church of Seekirchl its name. Below the Schlossberg, near the Seebach, is a radon -containing spring, that, under the name of the Franz Josef Spring, was mentioned in 1900 for the first time in the Directory of Spas of the Imperial-Royal Province of Tyrol and Vorarlberg ( Verzeichnis der Kurorte und Bäder der K.K. Statthalterei für Tirol und Vorarlberg ) and used until 1984 as

7544-541: The start of the winter timetable in 2010, Seefeld station became the highest Intercity-Express (ICE) stop in Europe. At weekends it is served by two ICE trains in each direction daily (2014 timetable). Three bus routes run by the Tyrol Transport Association stop in Seefeld, as does a long distance bus route (at the Rosshütte bus stop): The Bundesstraße 177 federal highway ( Seefelder Strasse ) to

7636-423: The temperature lowers. Upon condensation , it glows because of the intense radiation it produces. It is sparingly soluble in water, but more soluble than lighter noble gases. It is appreciably more soluble in organic liquids than in water. Its solubility equation is as follows: where χ {\displaystyle \chi } is the molar fraction of radon, T {\displaystyle T}

7728-618: The top station and then forks, the left branch making for the Reither Scharte and the right branch for the Nördlinger Hut . On the western side of the mountain, at between 1,500 and 1,700 metres, are the remains of old mine workings. The western side of the Härmelekopf is also part of the Rosshütte ski area . In addition to the cable car from the Rosshütte itself, there are lifts from Seefeld (the Hochangerbahn ) and

7820-657: The walks into the mountains are beautiful too, especially since the Karwendel is a huge nature reserve. Recommended walks include down through the Schlossbachklamm to Hochzirl (then the train back), and from the cable car stations down into the Eppzirlertal (if you're fairly fit). There are possibilities for multi-day walks through the Karwendel towards the Achensee . Together with eleven other towns Seefeld

7912-696: Was additionally fed between April and August from the Blauer Schrofen spring below the Seefelder Spitze. The additional water from the Kaltwassersee for snowmaking was raised in 2009 from 100,000 m to 165,000 m per year. Seefeld is on the Karwendel Railway with links to Munich via Garmisch-Partenkirchen and Innsbruck . It is also served by S-Bahn line 5 from Innsbruck to Scharnitz (to Garmisch-P.). From

8004-422: Was claimed to produce a higher fluoride as well which hydrolysed to form RnO 3 . While it has been suggested that these claims were really due to radon precipitating out as the solid complex [RnF] 2 [NiF 6 ] , the fact that radon coprecipitates from aqueous solution with CsXeO 3 F has been taken as confirmation that RnO 3 was formed, which has been supported by further studies of

8096-478: Was conducted in 1975 by a family firm based in Auland . Today about 900 participants in Seefeld and Reith are connected. DVB-T is transmitted by a transmitter on the Gschwandtkopf. Broadband access and HSPA is available in the entire permanent settlement of Seefeld at a rate of 42.2 MBit/s . It is naked DSL with symmetric bandwidth of up to 20 Mbit/s, ADSL up to 30 Mbit/s. Broadband internet

8188-444: Was obtained in 1962. Even today, the word radon may refer to either the element or its isotope Rn, with thoron remaining in use as a short name for Rn to stem this ambiguity. The name actinon for Rn is rarely encountered today, probably due to the short half-life of that isotope. The danger of high exposure to radon in mines, where exposures can reach 1,000,000  Bq /m , has long been known. In 1530, Paracelsus described

8280-422: Was predicted to have an even lower enthalpy of formation than the difluoride. The [RnF] ion is believed to form by the following reaction: For this reason, antimony pentafluoride together with chlorine trifluoride and N 2 F 2 Sb 2 F 11 have been considered for radon gas removal in uranium mines due to the formation of radon–fluorine compounds. Radon compounds can be formed by

8372-425: Was the fifth radioactive element to be discovered. First known as "emanation", the radioactive gas was identified during experiments with radium, thorium oxide, and actinium by Friedrich Ernst Dorn , Rutherford and Owens, and André-Louis Debierne , respectively, and each element's emanation was considered to a separate substance: radon, thoron, and actinon. Sir William Ramsay and Robert Whytlaw-Gray considered that

8464-490: Was the heaviest known gas. They wrote that " L'expression l'émanation du radium est fort incommode " ("the expression 'radium emanation' is very awkward") and suggested the new name niton (Nt) (from Latin : nitens , shining) to emphasize the radioluminescence property, and in 1912 it was accepted by the International Commission for Atomic Weights . In 1923, the International Committee for Chemical Elements and International Union of Pure and Applied Chemistry (IUPAC) chose

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