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| A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | R | S | T | U | V | X | Z | ||
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| Selenium | Sélénium | Selenij | Selenio | Selen | ||||||||||||||||||||
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Se Selenum |
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- Selenium was discovered by Jöns Jakob Berzelius (Sweden) in 1817. The origin of the name comes from the Greek word selene meaning moon. It is soft metalloid similar to sulfur. Ranges from grey metallic to red glassy appearance. Unaffected by water. Soluble in alkalis and nitric acid. Burns in air. Toxic by inhalation or ingestion.
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CHALKOGENE ELEMENT | |
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| Relative Atommasse: | 78.96(3) | Elektronenkonfiguration: | [Ar] 3d10 4s2 4p4 |
| Oxidationszustände: | -2 +4 +6 | Elekronegativität: | 2.55 |
| Wärmeleitfähigkeit: | 2.04 W m-1 K-1 | Elektrische Widerstandskraft (20 °C): | 12 μΩcm |
| Atomradius: | 116 pm | Zustand (20 °C): | fest |
| Dichte (g dm-3): | 4790 (grey, 293 K) 3987 (m.p.) |
Atomvolumen (cm3 mol-1): | 16.48 (grey, 293 K) 19.80 (m.p.) |
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THERMISCHE EIGENSCHAFTEN | |
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| Schmelzpunkt: | 221 °C | Bildungsenergie: | 5.1 kJ mol-1 |
| Siedepunkt: | 685 °C | Verdampfungsenergie: | 90 kJ mol-1 |
| Kritische Temperatur: | 1484 °C | Zerstäubungsenergie: | 226.4 kJ mol-1 |
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IONISIERUNGSENERGIE UND HÄUFIGKEIT | |
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| 1. Ionisierungenergie: | 940.97 kJ mol-1 | Häufigkeit des Elements (Luft): | - ppm |
| 2. Ionisierungenergie: | 2044.54 kJ mol-1 | Häufigkeit des Elements (Erdkruste): | 0.05 ppm |
| 3. Ionisierungenergie: | 2973.74 kJ mol-1 | Häufigkeit des Elements (Ozean): | - ppm |
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ISOTOPE | |
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Isotope | Relative Atommasse | Häufigkeit (%) |
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74Se | 73.922477(2) | 0.89(2) |
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76Se | 75.919214(2) | 9.36(11) |
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77Se | 76.919915(2) | 7.63(6) |
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78Se | 77.917310(2) | 23.78(9) |
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80Se | 79.916522(2) | 49.61(10) |
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82Se | 81.916700(2) | 8.73(6) |
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MINERALIEN UND GEBRAUCH | |
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- Selenium is obtained from lead, copper and nickel refining. Conducts electricity when struck by light. Light causes it to conduct electricity more easily. It is used in photoelectric cells, TV cameras, xerography machines and as a semiconductor in solar batteries and rectifiers. Also colours glass red. The price of 99.999 % pure amorphous selenium shot is 301.80 € for 1000 g.
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REDUKTIONSPOTENTIALE | |
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Balanced half-reaction | Eo / V | Anmerkung |
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SeO42- + 2H+ + 2e-  SeO32- + H2O |
+0.880 | |
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SeO42- + H2O + 2e- SeO32- + 2OH- |
+0.05 | |
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SeO42- + 3H+ + 2e- HSeO3- + H2O |
+1.075 | |
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SeO42- + 4H+ + 2e- H2SeO3 + H2O |
+1.15 | |
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HSeO4- + 3H+ + 2e- H2SeO3 + H2O |
+1.090 | |
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SeO32- + 6H+ + 4e- Se(s) + 3H2O |
+0.875 | |
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HSeO3- + 5H+ + 4e- Se(s) + 3H2O |
+0.778 | |
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H2SeO3 + 4H+ + 4e- Se(s) + 3H2O |
+0.740 | |
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SeO32- + 6H+ + 6e- Se2- + 3H2O |
+0.276 | |
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SeO32- + 7H+ + 6e- HSe- + 3H2O |
+0.414 | |
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HSeO3- + 6H+ + 6e- HSe- + 3H2O |
+0.349 | |
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HSeO3- + 7H+ + 6e- H2Se(g) + 3H2O |
+0.386 | |
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H2SeO3 + 6H+ + 6e- H2Se(g) + 3H2O |
+0.360 | |
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Se(s) + 2H+ + 2e- H2Se(g) |
- 0.369 | |
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Se(s) + 2e- Se2- |
- 0.924 | |
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Se(s) + H+ + 2e- HSe- |
- 0.510 | |
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Se(s) + 2H+ + 2e- H2Se(g) |
- 0.399 | |
