U+1D431 "𝐱" Mathematical Bold Small X Unicode Character

Unicode Version 18.0

𝐱
Source: Noto Sans Math Source: Browser Default

U+1D431 "𝐱" Mathematical Bold Small X is a typographic variant of the standard lowercase letter 'x', specifically designed for mathematical and scientific notation where a bold weight is required to distinguish variables, vectors, or other elements within complex formulas. It belongs to the "Mathematical Alphanumeric Symbols" block, which was added to Unicode to provide dedicated characters for mathematical formatting instead of relying on simple font styling. This allows text processing in plain text environments, such as in publishing or software algorithms, to reliably preserve the intended mathematical meaning and visual structure without losing formatting information.

Encodings

HTML Decimal Encoding
𝐱
HTML Hex Encoding
𝐱
UTF-8 Encoding
0xF0 0x9D 0x90 0xB1
UTF-16 Encoding
0xD835 0xDC31
UTF-32 Encoding
0x0001D431
C/C++/Java Escape
\ud835\udc31