U+1D6B5 "𝚵" Mathematical Bold Capital Xi Unicode Character

U+1D6B5 "𝚵" Mathematical Bold Capital Xi is a typographic variant of the Greek capital letter Xi, distinguished by a bold weight and designed for use within mathematical and scientific notation rather than for standard Greek text. It belongs to the Mathematical Alphanumeric Symbols block, encoded specifically to allow authors and typesetting systems to clearly distinguish between letters used as mathematical variables and ordinary text. This character is commonly employed in fields such as engineering, physics, and higher mathematics, where uppercase Xi often represents prominent concepts like the Riemann Xi function or large statistical sums, and its bold style helps reinforce its symbolic role in dense formulas.

General Properties

Code Point	U+1D6B5
Version Added	3.1
Name	Mathematical Bold Capital Xi
Block	Mathematical Alphanumeric Symbols
General Category	Uppercase Letter
Canonical Combining Class	Not Reordered
Bidirectional Class	Left To Right
Decomposition Type	Font
Decomposition Mapping	"Ξ" U+039E Greek Capital Letter Xi

Encodings

HTML Decimal Encoding	𝚵
HTML Hex Encoding	𝚵
UTF-8 Encoding	0xF0 0x9D 0x9A 0xB5
UTF-16 Encoding	0xD835 0xDEB5
UTF-32 Encoding	0x0001D6B5
C/C++/Java Escape	\ud835\udeb5

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	"ξ" U+03BE Greek Small Letter Xi
NFKC Simple Casefold	"ξ" U+03BE Greek Small Letter Xi
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	Rotated
Grapheme Base	Yes
Grapheme Cluster Break	Other
Word Break	Alphabetic letter
Sentence Break	Upper