Right Quaternion
A right quaternion is a quaternion whose scalar component is zero,
The angle of a right quaternion is 90 degrees. A right quaternion can also be thought of as a vector plus a zero scalar. Right quaternions may be put in what was called the standard trinomial form. For example, if Q is a right quaternion, it may be written as:
Read more about this topic: Classical Hamiltonian Quaternions, Classical Elements of A Quaternion, Quaternion