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Drawn identically; only what sits either side distinguishes chemistry from arithmetic.
Two short parallel lines. Between atoms in a structural formula they are a double bond — two shared electron pairs. Between quantities they assert equality. There is no visual difference at all, and none is needed, because the two never appear in the same expression.
Drawn identically; only what sits either side distinguishes a bond from an equality.
Drawn from the visual attributes recorded for each symbol. Only traits the two records disagree about are listed.
| Trait | Double bond notation | Equals sign |
|---|---|---|
| Symmetry | point | horizontal |
| Double bond notation | Equals sign | |
|---|---|---|
| What it means | Two shared electron pairs | The two sides are equal |
| What sits either side | Atoms | Quantities |
| Can it be tripled? | Yes — three lines is a triple bond | No |
| Visual difference | None | None |
| Relationship (from Symbolwise's records) | Commonly confused with Equals sign — Drawn identically; only what sits either side distinguishes a bond from an equality. | Commonly confused with Double bond notation — Drawn identically; only whether atoms or quantities sit either side distinguishes a chemical bond from an equality. |
Wikipedia · retrieved 2026-08-01
Tertiary reference. Used for what a symbol denotes in ordinary scientific practice and for which fields reuse it, never for a claim that any body assigns the letter its meaning.
Unicode Code Chart: Mathematical Operators (U+2200–U+22FF)
The Unicode Consortium · retrieved 2026-07-30
Authoritative for the character's code point, name and block only. Unicode assigns identity; it does not define what a symbol means in use.
Two horizontal bars is equality. Three is a congruence: a statement that two numbers leave the same remainder when divided by a modulus, and that modulus is written in brackets at the end of the line where it is the easiest thing on the page to overlook. Without the modulus the statement means nothing, and read as an ordinary equation it is simply false — which is why the extra bar matters more than its size suggests.
Count the horizontal strokes. One assigns a value. Two compare after converting types, which is where surprising results come from. Three compare without converting, so a string and a number are never equal. Miscounting is among the most common mistakes made by people new to the language, and nothing in the shape warns you.
Between two quantities, two level strokes assert that they are equal. Enclosed in a circle on a licensed work, the same two strokes are the no-derivatives condition: the work may be shared, but modified versions may not be distributed. Adapting it privately is not restricted — the condition is about sharing the result.
Look for the horizontal line. Fire is a plain upward triangle; air is the same triangle with a bar drawn across its upper part. Dropping the bar is the commonest error in reproductions of the element set, and it turns air into fire.