Using the lattice custom command for hcp structure

Dear lammps users,

I have a problem with setting up a HCP lattice by the lattice custom command. the positions of atoms and also the transition vectors(lattice parameters) of the structure are below: ( they belong to the pure Ti )

Ti 0.00000000 1.70318329 1.17150000
Ti 1.47500000 0.85159165 3.51450000
Tv 2.95000000 0.00000000 0.00000000
Tv -1.47500000 2.55477494 0.00000000
Tv 0.00000000 0.00000000 4.68600000

I have used this command : lattice custom 2.95 a1 2.95 0.0 0.0 a2 -1.475 2.55 0.0 a3 0.0 0.0 4.686 &
basis 0.0 1.703 1.171 basis 1.475 0.851 3.514

but I got an error " illegal lattice command ".

Can anybody help me solving the problem and tell me my mistake?

Thanks,
Nazanin

All basis values are between 0 and 1 as they
represent fractional positions within the unit cell.

See the
lattice doc page for details.

Steve