In this physical review B paper, the authors mentioned that the local symmetry of anatase TiO2 is D2d point group. Also, in this applied physics letters paper, the authors mentioned that the symmetry of the Ti$^{4+}$ ion in anatase TiO2 is D2d point group, and illustrated this using the conventio...

My school teacher told us this and I couldn't get his reason, The average distance of electron (belonging from the same orbit) from the nucleus decreases with the increase in the value of angular momentum quantum number for the orbital I don't understand how is l related to the distance from nucl...