Mathematical Bold Italic Capital Q
HTML Entity Browser Test:

U+1D478 is the Unicode hex value of the character Mathematical Bold Italic Capital Q, which is categorized as "uppercase letter" in the Unicode 6.0 character table.

In addition, U+1D478 is a composite character comprising of one or more other Unicode characters modified or combined.

Unicode Character Information
Unicode Hex U+1D478
General Category Uppercase Letter [Code: Lu]
Canonical Combining Class 0
Bidirectional Category L
Decomposition Mapping <font> 0051
Mirrored N
Unicode Character Encodings
Mathematical Bold Italic Capital Q HTML Entity &#119928; (decimal entity), &#x1D478; (hex entity)
Windows Key Code Alt 119928 or Alt +1D4781
Programming Source Code Encodings Python hex: u"\u1D478", Hex for C++ and Java: "\u1D478"
UTF-8 Hexadecimal Encoding 0xF09D91B8
1 To type a Unicode symbol in Windows, hold down the ALT key and enter the decimal or hexadecimal code provided using the numeric keypad. The decimal alt code (Alt 119928) will only work on computers with support for this Unicode character in the active code page. The hexadecimal alt code (Alt +1D478) will work for all Unicode characters provided Hex input from the numeric keypad is enabled.
* If the Mathematical Bold Italic Capital Q character does not display correctly in your browser, you may not have a Unicode font on your system that supports this particular symbol.