Figure 8
Ge—O bond lengths of the (a) Ge3 and (b) the Ge4 site of Cu2Fe2Ge4O13 as a function of temperature and variation of the tetrahedral angle variance TAV (left scale), and the tetrahedral quadratic elongation TQE (Robinson et al., 1971; right scale) for the (c) Ge2 and (d) for the Ge4 site. |