U+2145 "ⅅ" Double-Struck Italic Capital D Unicode Character
Unicode Version 17.0
ⅅ
U+2145 "ⅅ" Double-Struck Italic Capital D is a typographic variant of the capital letter D, rendered in a double-struck (or blackboard bold) style with an italic slant, and it is primarily used in mathematical and scientific notation to denote the set of real numbers when combined with a special double-struck R or, more specifically, to represent the differential operator in calculus contexts where a formal distinction from the ordinary letter d is desired. This character is part of the Letterlike Symbols block within Unicode, and its design mimics the bold chalkboard script often found in textbook equations.
General Properties
| Code Point | U+2145 |
| Version Added | 3.2 |
| Name | Double-Struck Italic Capital D |
| Block | Letterlike Symbols |
| General Category | Uppercase Letter |
| Canonical Combining Class | Not Reordered |
| Bidirectional Class | Left To Right |
| Decomposition Type | Font |
| Decomposition Mapping | "D" U+0044 Latin Capital Letter D |
Encodings
| HTML Decimal Encoding | ⅅ |
| HTML Hex Encoding | ⅅ |
| UTF-8 Encoding | 0xE2 0x85 0x85 |
| UTF-16 Encoding | 0x2145 |
| UTF-32 Encoding | 0x00002145 |
| C/C++/Java Escape | \u2145 |
Unicode Properties
| NFC Quick Check | Yes |
| NFD Quick Check | Yes |
| Numeric Type | None |
| Numeric Value | NaN |
| Line Break | Alphabetic |
| Uppercase | Yes |
| Cased | Yes |
| Changes When NFKC Casefolded | Yes |
| NFKC Casefold | "d" U+0064 Latin Small Letter D |
| NFKC Simple Casefold | "d" U+0064 Latin Small Letter D |
| Script | Common |
| Script Extensions | Common |
| Indic Syllabic Category | Other |
| ID Start | Yes |
| XID Start | Yes |
| ID Continue | Yes |
| XID Continue | Yes |
| Alphabetic | Yes |
| Math | Yes |
| Other Math | Yes |
| Vertical Orientation | Upright |
| Grapheme Base | Yes |
| Grapheme Cluster Break | Other |
| Word Break | Alphabetic letter |
| Sentence Break | Upper |