Liquefication of noble gases

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Liquefication of noble gasses :

Due to to weak intermolecular Ven der waals forces of attraction these gases possess very low melting points and boiling points. However, the melting point and boiling point of these gasses increase down the group from He to Rn which is due to increase in the size of the atoms. 

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Siemens Ozoniser how Siemens Ozoniser work

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Rutile structure

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Rutile structure: The radius radio is in the range 0.73 to 0.41. in rutile (TiO²) each Ti⁴+ ion is octahedrally surrounded by six O²- ions whereas each other O²- ion is surrounded by only three Ti⁴+ ions arranged at the tree corners of a plane triangle. The Co-ordination number of Ti⁴+ and O²+ ions are 6 and 3, respectively. It is not exactly a close packed structure. Ti⁴+ ions in rutile may however, be considered as forming a sufficiently distorted body centred cubic lattice.           Example  compounds  having radius ratio below 0.41 are SiO² and BeF² but these are only a few. The Co-ordination number of Si⁴+ and Be²+ is four and that of O²- is two. However, these are appreciably co-valent.
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Paramagnetic substances

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Paramagnetic substances:   The substances which are weakly attracted by magnatic lines of force are called paramagnetic substances and this phenomenon is called paramagnetism. These substances possesses permanent magnetic dipoles due to the presence of unpaired electrons. These substances lose their magnetic behaviour in the absence of an external magnetic field i.e. their magnetic behaviour is temporary. Examples, many transition metals and their ions i.e. TiO², VO², CuO, FeSO⁴ etc.
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