C# defines the following character escape sequences:

• \' - single quote, needed for character literals
• \" - double quote, needed for string literals
• \\ - backslash
• \0 - Unicode character 0
• \a - Alert (character 7)
• \b - Backspace (character 8)
• \f - Form feed (character 12)
• \n - New line (character 10)
• \r - Carriage return (character 13)
• \t - Horizontal tab (character 9)
• \v - Vertical quote (character 11)
• \uxxxx - Unicode escape sequence for character with hex value xxxx
• \xn[n][n][n] - Unicode escape sequence for character with hex value nnnn (variable length version of \uxxxx)
• \Uxxxxxxxx - Unicode escape sequence for character with hex value xxxxxxxx (for generating surrogates)

Of these, \a, \f, \v, \x and \U are rarely used in my experience.

[Author: Jon Skeet]