Oh man, I loved the Yellow and Orange dragons from the 80s! Especially the orange one:
Dragon Magazine 248 with my commentary in bold said:
An orange dragon's breath weapon is a 60' long stream of pure liquid sodium, five feet wide at the dragon's mouth. Sodium burns when exposed to air; the oily saliva of the dragon prevents premature ignition in the dragon's mouth. The sodium itself is stored in the digestive tract in a nearly solid state and is not liquefied until powerful gastric and esophageal contractions bring it up to the mouth. (Thank you, Richard, for this entirely necessary forensic tidbit.)
The orange dragon is a crossbreed of yellow and red dragons. Its sodium breath weapon is a result of its yellow parent's sodium chloride (salt) processing ability and its red parent's fire ability. The combination allows masses of metallic sodium to be separated out from the salt.
Creatures hit by this sodium stream are drenched, and within two melee rounds the saliva evaporates and the sodium is exposed to the air, bursting into engulfing flame. Creatures saving vs. breath weapon suffer half damage. (That's right, this dragon's breath weapon is a friggin' delayed-blast fireball!)
Sodium explodes when it comes in contact with water, so if well-meaning comrades of the victims try to wash off the sodium before it ignites, it instead explodes. The resulting blast causes damage equal to the damage the original target(s) would have suffered when bursting into flame to everything within a 15' radius. (And it's also a boobytrap!)
The only practical way (excuse the interruption...but did you just say 'practical way'? Go on, tell the people what you mean by PRACTICAL) to prevent a victim from catching fire is immediately to drench him or her in oil to prevent the sodium from contacting the air. (There is, of course, an element of risk in this procedure, should the sodium ignite--a 1 in 8 chance--as the oil is being poured. All clothing and armor must be removed and carefully cleaned of sodium while still oil-covered, requiring 8 + 1d8 (9-16) turns. (Yep, that all sounds totally practical.) This can be hazardous if done while the orange dragon continues its attack. (No s---, Sherlock.)
That one's hard to place; the original article says it is a chromatic, but a later version says it isn't. I put it in the Renegade dragons category instead (for unclassified dragons), so it'll show up later.
In case it needs to be said, Tiamat is in there because she is listed with the Chromatic dragons; all the uniques will be listed with their respective groupings: Bahamut with the metallics, Sardior with the gems, Khaylus with the cosmics, etc. Chromatics and metallics are somewhat strange in that each has two uniques: Tiamat and Rahab for the chromatics, and Bahamut and Ahi for the metallics.