Black-letter capital I (ℑ) is the Unicode character at U+2111 in Letterlike Symbols. Official name: BLACK-LETTER CAPITAL I — a Fraktur-style capital I. In mathematics it often denotes the imaginary part of a complex number.
Remember
Character ℑ
Unicode U+2111
Named entity ℑ (also ℑ · ℑ)
Hex entity ℑ
Decimal ℑ
CSS escape \2111
Not the same I · ℐ · ℜ
Prefer ℑ in HTML markup (aliases ℑ and ℑ are the same glyph). Numeric forms and typing ℑ in UTF-8 also work. Use it for math notation or black-letter style — not as a stand-in for Latin I.
Using Named Entity: ℑ
Using Hex Code: ℑ
Using HTML Code: ℑ
Using CSS Entity: ℑ
Typed directly: ℑ
Math: ℑ(z) = y
How It Works
1. Named:ℑ is the clearest HTML form for U+2111. ℑ and ℑ are aliases for the same character.
2. Hex:U+2111 → ℑ in HTML. Same glyph as the named entity.
3. Decimal: same code point as 8465 → ℑ. Same glyph as hex and named.
4. CSS: use \2111 in content (not an HTML entity). #point::after appends that ℑ after the paragraph text.
5. Typed / math: paste ℑ in UTF-8, or write expressions like ℑ(z) = y for imaginary-part notation.
Pitfalls & Tips
Common mistakes when working with U+2111.
vs I
Not a Latin letter I
Plain I (U+0049) is a different character. Use ℑ only when you need the black-letter / imaginary-part symbol.
vs ℐ
Not script capital I
ℐ (ℐ) is a script (calligraphic) form. ℑ is black-letter (Fraktur).
vs ℜ
Not the real-part symbol
ℜ (ℜ) is black-letter R for the real part. Pair them carefully in complex-number text.
Name
ℑ is not an “image” tag
The entity name ℑ means this letterlike symbol, not an <img> element. Do not confuse the two.
Fonts
Needs Letterlike font coverage
Some UI fonts omit U+2111. Prefer a stack that includes a math-capable font if the glyph must always show.
CSS vs HTML
Do not mix escapes
\2111 belongs in CSS strings. ℑ / ℑ / ℑ belong in HTML.
Compatibility
Browser Support
Black-letter capital I (U+2111) and its entity forms (ℑ, ℑ, ℑ, CSS \\2111) are supported in all mainstream browsers. Visible glyphs depend on Letterlike / math font coverage.
✓ Universal support
Black-Letter Capital I (ℑ)
Encode with named, hex, decimal, CSS escape, or type the character — same code point everywhere encoding is supported.
100%Browser coverage
Google ChromeSupported
Yes
Microsoft EdgeSupported
Yes
Mozilla FirefoxSupported
Yes
Apple SafariSupported
Yes
OperaSupported
Yes
Internet ExplorerAll versions
Yes
U+2111 / ℑFull support
Bottom line: Prefer ℑ in HTML. Use \\2111 only inside CSS content. Do not confuse with Latin I, script ℐ, or real-part ℜ.
Remember
Key Takeaways
Unicode: black-letter capital I is U+2111 (decimal 8465) — glyph ℑ.
Use ℑ (named), ℑ (hex), ℑ (decimal), type ℑ directly in UTF-8, or the CSS escape \2111 in content. Prefer ℑ in normal HTML. Aliases ℑ and ℑ also work.
U+2111 (BLACK-LETTER CAPITAL I). Hex 2111, decimal 8465. It belongs to Letterlike Symbols (U+2100–U+214F).
Yes. Use ℑ (preferred). Numeric forms ℑ and ℑ also work. HTML5 also defines ℑ and ℑ for the same character.
No. ℑ is the black-letter form (U+2111), often used for imaginary part. Plain I is U+0049. Script capital I is U+2110 (ℐ).
Use it in mathematical or academic text for the imaginary-part operator or black-letter I typography — not as a substitute for Latin I or script ℐ.
HTML entities (ℑ, ℑ, or ℑ) go in markup. The CSS escape \2111 goes in stylesheet strings (usually content on ::before/::after).
🤔
Did you know?
Black-letter capital I is Unicode U+2111 (decimal 8465) — glyph ℑ in Letterlike Symbols (U+2100–U+214F). HTML5 names it ℑ (also ℑ and ℑ). Official name: BLACK-LETTER CAPITAL I. In math it often marks the imaginary part of a complex number. Do not confuse with script capital I U+2110 (ℐ) or black-letter R U+211C (ℜ, real part).
