1Actually , in covalent azides suppose an element M makes bondwith the azide ion. then , the extra
electron from M enters the vacant antibonding molecular orbital of 'N'. thus the bond order of N - N bond
attached to M becomes becomes less than the bond order of adjacent N - N bond. thus , the bond
lengths become different also.
This gives rise to an unsymmetrical structure , with two unstable N - N bonds. thus , these covalent azides
are unstable and many of them are used as detonators and explosives.
While , the high negative charge density of azide ion enables it to form stable ionic azides.
