Table 4. Quality of the fit to the diffraction data after refinements of models of increasing complexity.

Given are R_F values of each order (|m|) of reflections, the number of parameters, _max, _min, the number of observed reflections N(obs) and the number of reflections N* with I > 5(I). Column gives R values of model D_r calculated for the N* reflections. Model A includes displacement modulations, model B adds modulations of harmonic ADPs, model C incorporates modulations of third-order ADPs while model C_r is restricted to significant third-order ADP parameters, and model D_r adds basic structure parameters for fourth-order anharmonic ADPs. For details see 2.2.

Present data	Model A	Model B	Model Cr	Model C	Model Dr	N(obs)	Model	N*
All	0.1047	0.0698	0.0634	0.0633	0.0563	6245	0.0525	5145
m = 0	0.0776	0.0606	0.0561	0.0560	0.0493	1825	0.0487	1773
|m| = 1	0.1227	0.0703	0.0651	0.0650	0.0561	2617	0.0537	2358
|m| = 2	0.2388	0.1218	0.0988	0.0963	0.0969	1088	0.0787	683
|m| = 3	0.4807	0.2565	0.2045	0.2030	0.2003	392	0.1708	215
|m| = 4	0.6203	0.3149	0.2890	0.3046	0.2987	86	0.2023	12
|m| = 5	0.3434	0.2137	0.1757	0.1771	0.1619	237	0.1278	104
No. of parameters	140	224	356	468	389
max (e3)	4.85	2.11	2.17	2.18	1.71		1.74
min (e3)	3.74	2.61	2.09	2.09	1.78		1.71