parameters for Fe4S4S(CH3)4 2-
MASS
FS    55.845
SB    32.066
SM    32.066
 
BOND
CT-SM  227.0    1.810
FS-SB    70.0     2.31
FS-SM   101.0     2.27
 
ANGLE
H1-CT-SM  50.0      109.50
CT-CT-SM  50.0      114.70
FS-SB-FS   12.2        73.0
FS-SM-CT   18.0       109.5
SB-FS-SB   18.0       104.6
SM-FS-SB   18.0       114.1

DIHE
X -CT-SM-X    1       0.0       180.0         2.0
X -FS-SB-X    1       0.0       180.0         2.0
X -FS-SM-X    1       0.0       180.0         2.0

IMPROPER
 
NONBON
  SB          2.0000  0.2500 
  SM          2.0000  0.2500 
  FS          1.10    0.0125