I have calculated Y2SiO5 with monoclinic system (Y1-Y2 two site, unique Si site and O1, O2, O3, O4 and O5 five site). Thus, I have used these parameters as a input file descriptions;
Monoclinic P, unique axis b
ibrav=13
celldm(2) = b/a
celldm(3)= c/a
celldm(5)=cos (ac) where beta is the angle between axis a and c
Dou you any comment for these chosen inputs
Many thanks