Octahedral, tetrahedral and square planar
Square planar, octahedral and tetrahedral
Octahedral, square planar and tetrahedral
Tetrahedral, square planar and octahedral
Ni2+ with NH3 shows Coordination Number = 6 forming [Ni(NH3)6]2+ (Octahedral)
Pt2+ with NH3 shows Coordination Number = 4 forming [Pt(NH3)4]2+ (Square planar)
Zn2+ with NH3 shows Coordination Number = 4 forming [Zn(NH3)4]2+ (Tetrahedral)
Therefore, the geometries of the ammonia complexes of Ni2+, Pt2+, and Zn2+ are Octahedral, Square planar, and Tetrahedral, respectively.