#ZMATRIX -- MOPAC style
 AM1
Ethane

C
C     1     r21
H     2     r32       1     a321
H     2     r32       1     a321      3  d4213
H     2     r32       1     a321      3 -d4213
H     1     r32       2     a321      3   60.
H     1     r32       2     a321      3  180.
H     1     r32       2     a321      3  d300

r21        1.5
r32        1.1
a321     109.5
d4213    120.0
d300     300.0