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The melting and boiling point of Lithium as compared to other members of the Alkali group metals is high. But, Lithium does not occur in the free state.

So, what does it mean that it has high melting and boiling point? How are its BP and MP measured if it isn't in the free state?

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    $\begingroup$ Litium does not occur in the free state in nature. But it can be made in the free state if it is protected from reaction with air and water. $\endgroup$ – matt_black Mar 9 '14 at 0:47
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Your premise here is wrong, pure metal Lithium exists and can be handled without much difficulty.

However, materials which are extremely reactive can always be kept in an inert gas when you want to measure their physical properties. Of course, there are compounds which can don't need an excuse to explode (and will explode in a vacuum/inert gas as well), in which case it is harder to find out BP/MPs (one can put them at low pressure and then extrapolate, but that's not as accurate).

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  • $\begingroup$ It is written in my course book that it does not occur in free state. $\endgroup$ – Rafique Mar 17 '13 at 19:44
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    $\begingroup$ @MuhammadRafique: What does it mean by "free state"? It may not occur in the free state naturally (as in, we need to synthesize it), but that is true for most elements. $\endgroup$ – ManishEarth Mar 17 '13 at 19:46
  • $\begingroup$ Agreed. Very few elements exist naturally in their free states. All but a select few (francium comes to mind) can be prepared by decomposing their compounds. Lithium is prepared by electrolysis of lithium chloride in the presence of potassium chloride. $\endgroup$ – Ben Norris Mar 17 '13 at 22:06
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    $\begingroup$ In fact I can't think of a single one outside of the noble gases that naturally occurs in pure elemental form. Most gaseous elements prefer to exist as diatoms in nature (oxygen gas is 100% oxygen, none of it "elemental" single atoms), and every other pure element I can think of is typically prepared from a naturally-occuring oxide or halide, with a few other chalcogen complexes in the mix such as sulfites/sulfates to make it interesting. There's just too much of everything else for any one thing to have the chance to remain in pure form. $\endgroup$ – KeithS Mar 18 '13 at 22:37
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    $\begingroup$ Platinum metals, gold, silver, copper occur in elemental form. $\endgroup$ – user2617804 Dec 14 '14 at 11:20

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