Halogen element, a liquid at room temperature (7)
I believe the answer is:
bromine
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">halogen element</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >'<span class="explanation-format__original">a liquid at room temperature</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ ></span>
(Other definitions for bromine that I've seen before include "Red liquid element" , "Element Br" , "Dark red toxic element" , "Halogen element" .)