  In order to study the magnetic and crystal structures in the
Nd{1-x}Sr{x}MnO{3} system, we have peformed neutron diffraction measurements on
melt-grown polycrystalline samples with 0.49 < x < 0.75. As a function of hole
concentration x, the system shows systematic transformation of magnetic and
crystal structures, which is consistently explained by the change of the
character of Mn eg orbitals. With increasing x, the Nd{1-x}Sr{x}MnO{3} system
exhibits a metallic ferromagnetic state, a metallic A-type AFM state, and then
an insulating C-type AFM state. The CE-type charge-ordered AFM state was
observed only in the vicinity of x=1/2, and it coexists with the A-type AFM
state for x > 1/2, indicating that the energy difference between these two
states is extremely small. We also found that the MnO{6} octahedra are apically
compressed in the CE-type and A-type AFM states due to the d(3x2-r2)/d(3y2-r2)
or d(x2-y2) orbital orderings, respectively, whereas they are apically
elongated by the rod-type d(3z2-r2) orbital ordering in the C-type AFM state.
In addition, a selective broadening of Bragg peaks was observed in the C-type
AFM phase, and its x dependence strongly suggests the charge ordering for a
commsurate value of the hole concentration at either x=3/4 or x=4/5.
