Are there any characters that can be encoded in UTF-16 but not UTF-8?

Question

Are there any characters that can be encoded in UTF-16 but not UTF-8

Answer 1

No.

UTF-* are encodings that can encode the full range of Unicode characters.
The differences between the encodings are how many bytes each character uses.

Answer 2

The only difference is the length of result and compatibility (utf-8 may easily be integrated with old ASCII-based software and utf-16 - with Win32 Unicode application). Both UTF-8 and UTF-16 represent short encoding of Unicode.