m 
Reflection plane, mirror plane (three dimensions) 
Reflection through a plane 

Reflection line, mirror line (two dimensions) 
Reflection through a line 
a, b or c 
`Axial' glide plane 
Glide reflection through a plane, with glide vector 
a 
⊥[010] or ⊥[001] 
½a 
b 
⊥[100] or ⊥[001] 
½b 
c 
⊥[100] or ⊥[010] 
½c 

⊥[10] or ⊥[110] 
½c 

⊥[100] or ⊥[010] or ⊥[0] 
½c, hexagonal coordinate system 

⊥[10] or ⊥[120] or ⊥[0] 
½c, hexagonal coordinate system 
n 
`Diagonal' glide plane (in noncentred cells only) 
Glide reflection through a plane, with glide vector 
⊥[001] 
½(a + b) 
e 
`Double' glide plane ⊥[001] (in centred cells only) 
Two glide reflections through planes with glide vectors ½a and ½b 
g 
Glide line (two dimensions) 
Glide reflection through a line, with glide vector 

⊥[01]; ⊥[10] 
½a; ½b 
1 
None 
Identity 
2, 3, 4, 6 
nfold rotation axis, n (three dimensions) 
Counterclockwise rotation of 360/n degrees about an axis 

nfold rotation point, n (two dimensions) 
Counterclockwise rotation of 360/n degrees about a point 

Centre of symmetry, inversion centre 
Inversion through a point 
= m, , , 
Rotoinversion axis, 
Counterclockwise rotation of 360/n degrees around an axis, followed by inversion through a point on the axis 
2_{1}, 3_{1}, 3_{2}, 4_{1}, 4_{2}, 4_{3}, 6_{1}, 6_{2}, 6_{3}, 6_{4}, 6_{5} 
nfold screw axes, n_{p} 
Righthanded screw rotation of 360/n degrees around an axis, with screw vector (p/n)t; t is the shortest translation vector parallel to the axis in the direction of the screw 