How does ifort deal with kind(25, 1000) and kind (33)?

Hello 

I am not sure whether I understand how ifort deals with different kinds of variable.   What is the different between a real that uses kind(25,1000) and a real with kind(33)? When I see the outputs of range, precision, huge, tiny and kind, they seem to be the same for both variables.  Why can't I define kind(40)? How to use a real with 16 bits?   

Thanks fot the patience and help.

Cheers

Ed