There is no compound known as "disodium ammonium." This name is not chemically correct, and it doesn't represent a valid chemical formula.

Here's why:

* Sodium (Na) is a Group 1 alkali metal, forming a +1 cation (Na+).

* Ammonium (NH4) is a polyatomic ion with a +1 charge.

Because both ions have a +1 charge, they wouldn't combine to form a neutral compound.

Possible Misunderstandings:

* Perhaps you're thinking of sodium ammonium phosphate (NaNH4HPO4), which is a salt containing sodium, ammonium, and phosphate ions.

* It's also possible you meant sodium amide (NaNH2), a compound where sodium is bonded to an amide (NH2-) group.

If you can provide more context about what you're looking for, I can help you find the correct chemical formula.