The Avengers 188, October, 1979, page 18.

©Marvel Comics Group
"Elementary, Dear Avengers"
Writer: Bill Mantlo
Artists: John Byrne, Dan Green
and Frank Springer
Colorist: Bob Sharen
Letterer: Gaspar
Editor, Plotter: Jim Shooter

The Avengers (Captain America, Wonder Man, Ms. Marvel, Quicksilver, Scarlet Witch, Beast, Wasp and Falcon) are passing through Soviet airspace during the age of détente and SALT.  They are called upon to face the Elements of Doom, an experiment gone awry in a nuclear reactor.  The existence of these living elements is never really explained, but they appear to be an homage of sorts to the Metal Men.  The chemistry in this issue is quite accurate.  Radium is the leader of the group, who plans that "one hundred others must be brought to life."  Vanadium is depicted as a metal which "resists attack by corrosion, various acids" but is brittle enough to be shattered by a blow. 

Carbon can change his form from graphite to diamond.  Phosphorus is "an element which, in its normal state, explodes spontaneously on contact with the air."  Chlorine "is a very deadly gas."  Cobalt doesn't see much action.  The Elements of Doom are destroyed by splitting open the molten core of a fusion reactor with a laser, "and the eerie elementals are caught in a white-hot rain of nuclear plasma!  The thermonuclear mixture of electrons and charged atoms swiftly breaks down their atomic structures!"  The Elements of Doom reappear (out of continutity)  in a 1993 Charleston Chew promotional comic book, then more notably in 1997's Thunderbolts 6 and 7.