In order to produce smaller amounts of oxygen, O2 from the air by adsorption of other gases can be separated. These air flows through molecular sieves. In this case, nitrogen and carbon dioxide are adsorbed and only O2 and argon pass through. This is used in O2 concentrator mainly used medically (oxygen for energy).
An older method is based on chemical reactions barium oxide method. It is uneconomical due to high energy costs. For barium oxide is heated under air at 500 degrees C., the barium forms. When heated to 700 degrees C recorded earlier O2 is released by thermolysis again. Prior to development of Linde process, this method was the only way to pure O2 present.
Oxygen is not created in primordial nucleosynthesis, but is produced in relatively large amounts in giant stars by helium burning. It is first formed from three helium nuclei 12C (Triple-alpha process), which subsequently merged with another helium nucleus to 16O. 18O is formed by fusion of 4He with a 14N nucleus.
O2 is slightly soluble in water. The solubility depends on the pressure and the temperature. It increases with decreasing temperature and increasing pressure. At 0 degrees C and an O2 partial pressure of air of 212 hPa dissolve in pure water 14.16 mg / l oxygen. In oxygen-gas discharge Spectrum, the molecular orbitals of O2 are stimulated to emit light. The operating conditions are a pressure of 5-10 mbar, a high voltage of 1.8 kV, a current of 18 mA and a frequency of 35 kHz. During the recombination of ionized gas molecules, the characteristic color spectrum is emitted. In this case, a small part, caused reversibly formed by the supply of energy ozone.
The binding and the properties of O2 molecule can be well explained by the molecular orbital model. The s and p atomic orbitals of individual atoms are assembled to form bonding and antibonding molecular orbitals. The 1s and 2s orbitals of O2 atoms are each to . Sigma.. Sub. S and . Sigma.. Sub. S - bonding and antibonding molecular orbitals.
Since these orbitals are completely filled with electrons, they do not contribute to binding. From the 2p orbitals are a total of six molecular orbitals with different energy level. The orbitals have this same energy. Electrons are distributed in molecular orbitals, it comes to following breakdown of eight p-electrons. These two valence electrons determine the properties of O2 molecule. O2 has allowed a total of three and energetically accessible quantum states for the distribution of these electrons.
Occupation of energy levels of molecular orbitals of O2 in ground and excited states. In ground state the spins of two valence electrons of Hund's rule are arranged in parallel in obedience. It is a triplet state with the term symbol 3g. It is the state with the lowest energy. Through the two unpaired electrons, the two orbitals are half occupied. This caused some characteristic properties, such as the diradical character and the paramagnetism of O2 molecule.
The most common stable oxygen isotope 16O (99.76%), in addition still comes 18O (0.20%) and 17O (0.037%) before. In addition to the stable oxygen isotopes are still a total of 13 unstable, radioactive nuclides from 12O to 28O are known which are artificially produced. Their half lives often are only milliseconds to seconds, with two minutes 15O this case has the longest half-life, and is frequently used in positron emission tomography.
An older method is based on chemical reactions barium oxide method. It is uneconomical due to high energy costs. For barium oxide is heated under air at 500 degrees C., the barium forms. When heated to 700 degrees C recorded earlier O2 is released by thermolysis again. Prior to development of Linde process, this method was the only way to pure O2 present.
Oxygen is not created in primordial nucleosynthesis, but is produced in relatively large amounts in giant stars by helium burning. It is first formed from three helium nuclei 12C (Triple-alpha process), which subsequently merged with another helium nucleus to 16O. 18O is formed by fusion of 4He with a 14N nucleus.
O2 is slightly soluble in water. The solubility depends on the pressure and the temperature. It increases with decreasing temperature and increasing pressure. At 0 degrees C and an O2 partial pressure of air of 212 hPa dissolve in pure water 14.16 mg / l oxygen. In oxygen-gas discharge Spectrum, the molecular orbitals of O2 are stimulated to emit light. The operating conditions are a pressure of 5-10 mbar, a high voltage of 1.8 kV, a current of 18 mA and a frequency of 35 kHz. During the recombination of ionized gas molecules, the characteristic color spectrum is emitted. In this case, a small part, caused reversibly formed by the supply of energy ozone.
The binding and the properties of O2 molecule can be well explained by the molecular orbital model. The s and p atomic orbitals of individual atoms are assembled to form bonding and antibonding molecular orbitals. The 1s and 2s orbitals of O2 atoms are each to . Sigma.. Sub. S and . Sigma.. Sub. S - bonding and antibonding molecular orbitals.
Since these orbitals are completely filled with electrons, they do not contribute to binding. From the 2p orbitals are a total of six molecular orbitals with different energy level. The orbitals have this same energy. Electrons are distributed in molecular orbitals, it comes to following breakdown of eight p-electrons. These two valence electrons determine the properties of O2 molecule. O2 has allowed a total of three and energetically accessible quantum states for the distribution of these electrons.
Occupation of energy levels of molecular orbitals of O2 in ground and excited states. In ground state the spins of two valence electrons of Hund's rule are arranged in parallel in obedience. It is a triplet state with the term symbol 3g. It is the state with the lowest energy. Through the two unpaired electrons, the two orbitals are half occupied. This caused some characteristic properties, such as the diradical character and the paramagnetism of O2 molecule.
The most common stable oxygen isotope 16O (99.76%), in addition still comes 18O (0.20%) and 17O (0.037%) before. In addition to the stable oxygen isotopes are still a total of 13 unstable, radioactive nuclides from 12O to 28O are known which are artificially produced. Their half lives often are only milliseconds to seconds, with two minutes 15O this case has the longest half-life, and is frequently used in positron emission tomography.
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