U+2149 "ⅉ" Double-Struck Italic Small J Unicode Character

U+2149 "ⅉ" Double-Struck Italic Small J is a specialized typographic symbol that belongs to the Letterlike Symbols block, designed to represent the imaginary unit in mathematics, particularly in fields like physics and engineering where a blackboard bold italic style is used to denote complex numbers. Unlike the more common double-struck "i", this character provides a distinct, slanted variant for the letter "j", which is often preferred in electrical engineering to avoid confusion with the current symbol. Its inclusion in Unicode ensures consistent digital representation across different platforms and fonts, supporting precise mathematical notation in technical documentation and academic texts.

General Properties

Code Point	U+2149
Version Added	3.2
Name	Double-Struck Italic Small J
Block	Letterlike Symbols
General Category	Lowercase Letter
Canonical Combining Class	Not Reordered
Bidirectional Class	Left To Right
Decomposition Type	Font
Decomposition Mapping	"j" U+006A Latin Small Letter J

Encodings

HTML Decimal Encoding	ⅉ
HTML Hex Encoding	ⅉ
UTF-8 Encoding	0xE2 0x85 0x89
UTF-16 Encoding	0x2149
UTF-32 Encoding	0x00002149
C/C++/Java Escape	\u2149

Unicode Properties

NFC Quick Check	Yes
NFD Quick Check	Yes
Numeric Type	None
Numeric Value	NaN
Line Break	Alphabetic
Lowercase	Yes
Cased	Yes
Changes When NFKC Casefolded	Yes
NFKC Casefold	"j" U+006A Latin Small Letter J
NFKC Simple Casefold	"j" U+006A Latin Small Letter J
Script	Common
Script Extensions	Common
Indic Syllabic Category	Other
ID Start	Yes
XID Start	Yes
ID Continue	Yes
XID Continue	Yes
Soft Dotted	Yes
Alphabetic	Yes
Math	Yes
Other Math	Yes
Vertical Orientation	Upright
Grapheme Base	Yes
Grapheme Cluster Break	Other
Word Break	Alphabetic letter
Sentence Break	Lower