Table 1. Calculated stable isotope fractionation factors for Hg-bearing species relative to Hg⁰ (in per mil), including conventional mass-dependent effect (CMDE) fractionation factors ( ) and nuclear volume effect (NVE) fractionation factors ( ).

	This studya)					Schaubleb)					Wielderhold et al.c)
	0 °C	25 °C	100 °C	300 °C	1000 °C	0 °C	25 °C	100 °C	300 °C	1000 °C	25 °C
CMDE fractionation factor ()
Hg0	0	0	0	0	0	0	0	0	0	0
Hg2+	0	0	0	0	0	0	0	0	0	0
HgCl2	1.00	0.84	0.55	0.24	0.05	1.08	0.92 ± 0.1	0.60	0.26	0.05	0.84
HgBr2	0.88	0.74	0.48	0.21	0.04	0.95	0.80 ± 0.1	0.51	0.22	0.04
Hg(CH3)Cl	1.02	0.87	0.57	0.25	0.05	1.04	0.89 ± 0.1	0.58	0.25	0.05
Hg(CH3)2	1.13	0.97	0.64	0.28	0.06	1.14	0.97 ± 0.1	0.65	0.29	0.06
HgCl3−	0.64	0.54	0.35	0.15	0.03
HgCl42−	0.49	0.41	0.26	0.11	0.02	0.67	0.56+0.7/−0.1	0.36	0.15	0.03	0.40
HgBr3−	0.58	0.49	0.31	0.13	0.03
HgBr42−	0.42	0.35	0.22	0.09	0.02
Hg(H2O)62+	0.71	0.60	0.39	0.17	0.03	1.13	0.96 ± 0.4	0.62	0.27	0.05
Hg(OH)2	1.54	1.32	0.88	0.39	0.08						1.19
NVE fractionation factor ()
Hg0	0	0	0	0	0	0	0	0	0	0
Hg2+	3.94	3.61	2.89	1.88	0.85	3.47	3.17 ± 0.6	2.54	1.65	0.74
HgCl2	1.58	1.45	1.16	0.75	0.34	1.39	1.27 ± 0.3	1.02	0.66	0.30	1.25
HgBr2	1.53	1.40	1.12	0.73	0.33	1.34	1.23 ± 0.2	0.98	0.64	0.29
Hg(CH3)Cl	0.99	0.91	0.73	0.47	0.21	0.88	0.80 ± 0.2	0.64	0.42	0.19
Hg(CH3)2	0.71	0.65	0.52	0.34	0.15	0.62	0.57 ± 0.1	0.45	0.30	0.13
HgCl3−	2.33	2.14	1.71	1.11	0.50
HgCl42−	2.76	2.53	2.02	1.31	0.59	2.42	2.22 ± 0.4	1.77	1.16	0.52	2.23
HgBr3−	2.20	2.01	1.61	1.05	0.47
HgBr42−	2.60	2.38	1.91	1.24	0.56
Hg(H2O)62+	3.45	3.16	2.52	1.64	0.74	3.01	2.75 ± 0.6	2.20	1.43	0.64
Hg(OH)2	1.22	1.12	0.90	0.58	0.26						1.00
Total fractionation factor ()
Hg0	0	0	0	0	0	0	0	0	0	0
Hg2+	3.94	3.61	2.89	1.88	0.85	3.47	3.17 ± 0.6	2.54	1.65	0.74
HgCl2	2.58	2.29	1.71	0.99	0.39	2.47	2.19 ± 0.3	1.62	0.92	0.35	2.09
HgBr2	2.41	2.14	1.60	0.94	0.37	2.29	2.03 ± 0.2	1.49	0.86	0.33
Hg(CH3)Cl	2.01	1.78	1.30	0.72	0.26	1.92	1.69 ± 0.2	1.22	0.67	0.24
Hg(CH3)2	1.84	1.62	1.16	0.62	0.21	1.76	1.54 ± 0.1	1.10	0.59	0.19
HgCl3−	2.97	2.68	2.06	1.26	0.53
HgCl42−	3.25	2.94	2.28	1.42	0.61	3.09	2.78+0.8/0.4	2.13	1.31	0.55	2.63
HgBr3−	2.78	2.50	1.92	1.18	0.50
HgBr42−	3.02	2.73	2.13	1.33	0.58
Hg(H2O)62+	4.16	3.76	2.91	1.81	0.77	4.14	3.71 ± 0.7	2.82	1.70	0.69
Hg(OH)2	2.76	2.44	1.78	0.97	0.34						2.19

^aCalculated with <r²> values of Fricke and Heilig⁴¹ by using the software package DIRAC13.1.

^bCalculated with <r²> values of Angeli⁴² by using the software package DIRAC04 by Schauble⁴.

^cCalculated with <r²> values of Fricke and Heilig⁴¹ by using the software package DIRAC08 by Wiederhold et al.³⁵.