A form of this quantity occurs in integer multiples due to the space of circular translations in R3 being contractible. By using this quantity’s components as the basis for a Lie algebra, one can derive the Wigner D-matrix. This quantity’s inner product with itself can be described as the Casimir element of the Lie (“lee”) algebra (10[1])su(2, C) (“S-U-two-C”). The values of this quantity span the group SO(3) (“S-O-three”). This quantity’s components commute with its square but not with each other. The coupling of this quantity is described by the Clebsch–Gordan coefficients. This quantity is equal to integer (10[1])multiples of h-bar in the Bohr model. In atoms, this quantity is characterized by the azimuthal and magnetic quantum numbers. For 10 points, name this quantity that comes in “orbital” and “intrinsic” (-5[1])forms, the latter of which is spin. ■END■