Olivine interatomic distances

In olivine, 24 independent interatomic distances must be evaluated in order to define the structure. For all 24 distances (Z)y) plus cell edges and volume, regressions of the following type may be proposed ... 

Della Giusta A., Ottonello G, and Secco L. (1990). Precision estimates of interatomic distances using site occupancies, ionization potentials and polarizability in Pbnm silicate olivines. Acta Cryst., B46 160-165. 

Figure 5.8 The crystal structure of olivine, (a) The structure projected onto (100) showing serrated chains of octahedra running parallel to the c axis (b) oxygen coordination polyhedra projected about the Ml and M2 positions. Metal—oxygen distances in each coordination site are indicated. Cell parameters and interatomic distances are for fay-alite (from Smyth Bish, 1988).

We use the structural data determined by Streltsov et al. [86] as a standard reference (Table 7.1). The orthorhombic unit cell of the olivine stmcture contains 28 atoms (Z = 4). Structural parameters and interatomic distances are listed in Tables 7.2 and 7.3. Fe-0 distances range from 2.064 to 2.251 A. The Fe-Fe separation in LiFeP04 is large (3.87 A). 

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