Table 1B.

MIRAS phasing statistics

	HgCl2	Thiomersal	HgI2	PCMBS
No. of heavy atom sites	2	7	2	2
R_Cullis (acentric)a	0.65	0.67	0.73	0.69
R_Cullis (centric)	0.75	0.78	0.77	0.77
Phasing power (centric)b	1.51	1.42	1.40	1.42
Phasing power (acentric)	1.24	1.19	1.12	1.16
R_Cullis anomalous	0.91	0.91	0.93	0.91

^a$R\_Cullis=\Sigma \left|\right|F_{\text{PH}}\pm F_{\text{P}}|-|F_{\text{H}}{|}_{\text{calc}}|/\Sigma |F_{\text{PH}}\pm F_{\text{P}}|\text{.}$

^bPhasing Power = ${[\Sigma F_{\text{H}}^2/\Sigma (|F_{\text{PH obs}}|-|F_{\text{PF calc}|}{)}^2]}^{1/2}$, where F_PH and F_H are the derivative and calculated structure factors respectively.