I (Built-in Mathematica Symbol)

I represents the imaginary unit Sqrt[-1].

BesselI (Built-in Mathematica Symbol)

BesselI[n, z] gives the modified Bessel function of the first kind I_n (z).

\[ImaginaryI] (Mathematica Character Name)

Unicode: F74E. Alias: Esc ii Esc. Letter-like form with built-in value.  is interpreted by default as the symbol I, representing Sqrt[-1].

\[DotlessI] (Mathematica Character Name)

Unicode: 0131. Letter. Used when an i will have an overscript on top. May or may not match the ordinary i from the text font.

\[IGrave] (Mathematica Character Name)

Unicode: 00EC. Alias: Esc i` Esc. Letter. Included in ISO Latin-1.

\[IHat] (Mathematica Character Name)

Unicode: 00EE. Alias: Esc i^ Esc. Letter. Included in ISO Latin-1.

\[IAcute] (Mathematica Character Name)

Unicode: 00ED. Alias: Esc i' Esc. Letter. Included in ISO Latin-1.

\[CapitalIAcute] (Mathematica Character Name)

Unicode: 00CD. Alias: Esc I' Esc. Letter. Included in ISO Latin-1.

\[CapitalIGrave] (Mathematica Character Name)

Unicode: 00CC. Alias: Esc I` Esc. Letter. Included in ISO Latin-1.

\[CapitalIHat] (Mathematica Character Name)

Unicode: 00CE. Alias: Esc I^ Esc. Letter. Included in ISO Latin-1.