Application of a modified Oszlanyi and Suto ab initio charge-flipping algorithm to experimental data

The structures of two crystals have been solved using a new iterative phasing method. The iterative phasing algorithm is developed from the `charge-flippingʹ method proposed by Oszlanyi & Suto [Acta Cryst. (2004), A60, 134-141]. Positivity and pointatom constraints are incorporated within this extremely simple and effective algorithm by flipping (sign reversal) of less-positive density values during the iterations. Convergence is reliably achieved and the two structures were solved. This structure solution method does not require information on atomic scattering factors or symmetry. Heavy atoms can be distinguished from light ones by their charge-density values.