The Lewis structure of cyanide anion is #""^(-):C-=N#. There are 7 electrons formally associated with the carbon atom, which makes this centre an anion. (Why #7#? there are 2 lone pairs electrons, and the carbon atoms SHARES 3 from the triple bond; there are 2 inner core electrons, i.e. #1s^2# with respect to atomic carbon, and thus 7 electrons, an excess of 1 over the nuclear charge, #Z=6#).
Cyanide inhibits the biological function of #"cytochrome C"# by binding to the site that normally binds to dioxygen, thereby preventing respiration. Hydrogen cyanide is quite volatile, and has the smell of almonds.
Back in the day, when you used cyanide solutions, and cyanide gas in the lab, you were obliged to have #"Mohr's salt"# on hand, i.e. an #Fe^(II+)# salt to be freshly prepared as an aqueous solution, which, if consumed, would bind to the cyanide you have already consumed, rendering the cyanide biologically inactive. An #Fe^(III+)# salt would be an even better Lewis acidic reagent, however, #Fe^(III+)# gives solutions that are too acidic for consumption. These days the use of cyanide antidotes are not recommended, at least according to the recent literature.
For further details see,
#"Nicholson P. J., Ferguson-Smith J., Pemberton M. A. et al.,"#
#"Occup. Med."# 1994, 44 , 125-128.
No doubt in cases of cyanide poisoning, the paramedics would put the victim onto bottled oxygen pdq. If anyone here is a paramedic, or knows a paramedic, their input would be appreciated.