4

Si     -0.211973806835931      0.261253996680072      0.185843766726636
Si      1.683628102820145      1.653565791793738      0.146850091681325
Si      1.769594050077381      0.368048516534373      1.354024785857218
Si      0.388918589954730      1.606624886452935      1.653002310766441