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Air pollution impacts on ozone
Published in Abhishek Tiwary, Ian Williams, Air Pollution, 2018
Allotropy is the property of some chemical elements to exist in two or more different forms. These different forms of an element are known as allotropes. Allotropes are different structural modifications of an element; essentially the atoms of the element are bonded together in a different manner, for example, carbon, where allotropes include diamond, graphite, graphene and the fullerenes. For some elements, allotropes have different molecular formulae which can even persist in different phases; the two best-known allotropes of oxygen (dioxygen, O2, and ozone, O3), can exist in the solid, liquid and gaseous states. Other known allotropes of oxygen include: Atomic oxygen (O); more accurately denoted O(3P), O(3P) or O((3)P). This allotrope is very reactive, as the single atoms of oxygen tend to quickly bond with nearby molecules. This allotrope does not exist naturally for very long on Earth’s surface.Singlet oxygen (dioxygen), which is the common name used for an electronically excited state of molecular oxygen (O2). The ground state – in which the total energy of the electrons cannot be lowered by transferring one or more electrons to different orbitals – is known as triplet oxygen but there are also two metastable states – states that spend an extended time in a configuration other than the ground state – called singlet oxygen [O(1D)].Tetraoxygen (O4), discovered in 2001. It is possible that O4 consists of two dumbbell-shaped O2 molecules held together by dispersion forces.Solid oxygen, which has six known distinct phases.
A review on surface modification methods of poly(arylsulfone) membranes for biomedical applications
Published in Journal of Biomaterials Science, Polymer Edition, 2021
Vahid Hoseinpour, Laya Noori, Saba Mahmoodpour, Zahra Shariatinia
Trioxide is one of the allotropes of oxygen containing three atoms of oxygen (O3), and compared with O2, it is more unstable. Trioxide has several consumer and industrial usages. It can be used for modifying the hydrophilicity by grafting some hydrophilic polymers onto ozone-treated poly(arylsulfone) membranes [29].