In chemistry, a zwitterion (/ˈtsvɪtər.aɪ.ən/ TSVIT-ər-eye-ən; from German zwitter [ˈtsvɪtɐ] "hybrid" and formerly called a dipolar ion) is a neutral molecule with a positive and a negative electrical charge, though multiple positive and negative charges can be present. Zwitterions are distinct from dipoles, at different locations within that molecule. Zwitterions are sometimes also called inner salts.
Unlike simple amphoteric compounds that might only form either a cationic or anionic species depending on external conditions, a zwitterion simultaneously has both ionic states in the same molecule.
Amino Acids are the best-known examples of zwitterions. These compounds contain an ammonium and a carboxylate group, and can be viewed as arising via a kind of intramolecular acid–base reaction: The amine group deprotonates the carboxylic acid.
The zwitterionic structure of glycine in the solid state has been confirmed by neutron diffraction measurements. At least in some cases, the zwitterionic form of amino acids also persists in the gas phase.
Comin' in easy on the sea train.
Walkin' out under the fog again,
And the sky don't explain
If I'm up or across or down, town around just like then.
The neon screen will never know when.
Be quiet or dream,
And just not crowd the scenes
Of my mind's sound.
I'm goin' under and comin' on out
To see you again.
My mind's been wanderin', but I'm about
To meet you again.
The rhythm of hearts plays in my veins
Like some long-gone lonesome sea train.
I'm only sure that the weather would break if I did.
They'll come easy, then go glad.
Your child at the window says the rain don't look sad,
And you ask me who's mad
As you show me your lost and found.
Down, you're bound again.
With your fan, my fire turns to wind
Your glass fills mine with sand,
You shout, "I'm not your land!"
And I hear the ground.
I'm a weeping shadows, feeling like a willow
Bearing Martha's flower; as the sun comes, I come.
Far across the street, clear across the stream,
The sun shall come.
If you're in a tree and the forest falls, who hears you?
[musical interlude]
And the hills meet the wind, making dew.
We see us again.
As the sun behind clouds, breaking through,
We're gonna meet them again.
The rhythm of hearts plays through my veins
Like some long-gone lonesome sea train.
Rain in the meadow beats the river to the ocean.