1 If the invitation says black tie, women should wear a floor-length, evening gown. 2  A tuxedo is mandatory if you're a man. 3  This is your chance to dress as if you were headed to the Oscars. 4  Black tie optional means that wearing a tuxedo or long evening gown is not mandatory, but guests should feel free to do so.
Ether is an organic functional group consisting of a disubstituted oxygen, or an oxygen atom bonded to 2 carbon atoms (if adjacent to a ketone, functional group is then called an ester).
Ester and ether are organic molecules with oxygen atoms. Both have the ether linkage which is âO-. Esters have the group âCOO. One oxygen atom is bonded to carbon with a double bond, and the other oxygen is bonded with a single bond. Since only three atoms are connected to the carbon atom, it has a trigonal planar geometry around it. Further, the carbon atom is sp2 hybridized.