4

Si     -0.177691561099719     -0.089508401935904     -0.277135798408386
Si      1.438580728146456      1.151773945077700      0.154887825454511
Si      1.559885403162094     -0.297542548239200      1.664310824750570
Si      0.032396223405463      1.488440649173399      1.532777132345812