# '\[ atomtypes \]' Invalid order for directive atomtypes **URL:** \ **Category:** User discussions\ **Tags:** grompp\ **Created:** [December 3, 2022, 4:55pm UTC](https://gromacs.bioexcel.eu/t/atomtypes-invalid-order-for-directive-atomtypes/5355 "2022-12-03T16:55:53Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![merry](https://avatars.discourse-cdn.com/v4/letter/m/e480ec/32.png) [@merry](https://gromacs.bioexcel.eu/u/merry)\ **Post date:** [December 3, 2022, 4:55pm UTC](https://gromacs.bioexcel.eu/t/atomtypes-invalid-order-for-directive-atomtypes/5355/1 "2022-12-03T16:55:53Z")
GROMACS version: 2019.4 GROMACS modification: No Hi. I get the itp file for my polymer (containing 305 atoms) using the PolyParGen ([http://polypargen.com](http://polypargen.com)), as follows: ; GENERATED BY PolyParGen 2022/11/29 12:31:04UTC ; Automatic parameter generation tool:LigParGen ; [atomtypes] ppg\_AAA H0 1.0080 0.000 A 2.50000E-01 1.25520E-01 ppg\_AAB C1 12.0110 0.000 A 3.50000E-01 2.76144E-01 ppg\_AAC O2 15.9990 0.000 A 2.90000E-01 5.85760E-01 ppg\_AAD O3 15.9990 0.000 A 3.12000E-01 7.11280E-01 ppg\_AAE H4 1.0080 0.000 A 0.00000E+00 0.00000E+00 ppg\_AAF H5 1.0080 0.000 A 2.50000E-01 1.25520E-01 ppg\_AAG C6 12.0110 0.000 A 3.50000E-01 2.76144E-01 ppg\_AAH O7 15.9990 0.000 A 2.90000E-01 5.85760E-01 ppg\_AAI C8 12.0110 0.000 A 3.55000E-01 2.92880E-01 ppg\_AAJ O9 15.9990 0.000 A 2.96000E-01 8.78640E-01 ppg\_AAK O10 15.9990 0.000 A 3.12000E-01 7.11280E-01 ppg\_AAL H11 1.0080 0.000 A 0.00000E+00 0.00000E+00 [moleculetype] ; Name nrexcl LIG 3 [atoms] ; nr type resnr residue atom cgnr charge mass 1 ppg\_AAB 1 LIG C004 1 -0.2390 12.0110 2 ppg\_AAA 1 LIG H003 1 0.0895 1.0080 3 ppg\_AAA 1 LIG H002 1 0.0896 1.0080 4 ppg\_AAA 1 LIG H001 1 0.0895 1.0080 5 ppg\_AAB 1 LIG C003 1 -0.1713 12.0110 6 ppg\_AAA 1 LIG H005 1 0.1197 1.0080 7 ppg\_AAA 1 LIG H004 1 0.1198 1.0080 8 ppg\_AAB 1 LIG C002 1 0.4357 12.0110 9 ppg\_AAC 1 LIG O000 1 -0.4147 15.9990 10 ppg\_AAB 1 LIG C001 1 0.0259 12.0110 11 ppg\_AAA 1 LIG H00Q 1 0.1045 1.0080 12 ppg\_AAA 1 LIG H00P 1 0.1045 1.0080 13 ppg\_AAB 1 LIG C000 1 -0.0078 12.0110 14 ppg\_AAA 1 LIG H00R 1 0.0873 1.0080 15 ppg\_AAA 1 LIG H000 1 0.0871 1.0080 16 ppg\_AAC 1 LIG O007 1 -0.3810 15.9990 17 ppg\_AAB 1 LIG C00G 1 0.0101 12.0110 18 ppg\_AAA 1 LIG H00T 1 0.0973 1.0080 19 ppg\_AAA 1 LIG H00S 1 0.0972 1.0080 20 ppg\_AAB 1 LIG C00H 1 0.0043 12.0110 21 ppg\_AAA 1 LIG H00V 1 0.0897 1.0080 . . . . . . Then, I manually created a topology file as follows: ; #include “lig.itp” ; Include Position restraint file #ifdef POSRES #include “posre.itp” #endif [system] ; Name Polymer [molecules] ; Compound #mols LIG 1 When I used the command: gmx\_mpi grompp -f min\_vac.mdp -c box.gro -p topol.top -o min\_vac.tpr I encountered with the following error: Fatal error: Syntax error - File lig.itp, line 5 Last line read: ‘[atomtypes]’ Invalid order for directive atomtypes How to resolve this issue? ---
**Author:** ![jalemkul](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/jalemkul/32/18_2.png) [@jalemkul](https://gromacs.bioexcel.eu/u/jalemkul)\ **Post date:** [December 3, 2022, 5:07pm UTC](https://gromacs.bioexcel.eu/t/atomtypes-invalid-order-for-directive-atomtypes/5355/2 "2022-12-03T17:07:43Z")
You need to `#include` a parent force field first, or manually define a `[defaults]` directive. You cannot being a topology with `[atomtypes]`.