. 2017 Jan 27;114(7):E1046–E1053. doi: 10.1073/pnas.1620427114

Table 2.

Composition, surface area, Mn AOS, wt% water loss, drop solution enthalpy, water-corrected drop solution enthalpy, formation enthalpy from the oxides (without and with oxidation reaction, and from the elements), and standard entropy for the nanophase samples

Composition^*	BET surface area,^† m²/g (m²/mol)	Mn AOS	TGA weight loss,^‡ [wt %]	ΔH_ds,^§ kJ/mol	ΔH_ds,_corr,^¶ kJ/mol	ΔH°_f-ox,^# kJ/mol	ΔH°_f-ox^_*,^\|\| kJ/mol	ΔH°_f,^** kJ/mol	S°₂₉₈,^†† J/mol⋅K
Na_0.09MnO_1.815·0.64H₂O	94.64 ± 0.69 (9,295.45)	3.54 ± 0.01	12.52	193.91 ± 2.01 (10)	149.68 ± 2.65	−56.01 ± 2.11	−79.08 ± 3.82	−703.29	102.82 ± 0.09
Na_0.08MnO_1.82·0.42H₂O	58.72 ± 0.18 (5,526.83)	3.56 ± 0.01	8.59	179.79 ± 1.85 (8)	150.71 ± 2.51	−55.09 ± 1.96	−78.92 ± 3.64	−639.19	86.97 ± 0.08
Na_0.08MnO_1.825·0.54H₂O	28.30 ± 0.20 (2,726.47)	3.57 ± 0.01	10.81	191.65 ± 1.66 (8)	154.53 ± 2.21	−58.19 ± 1.78	−82.66 ± 3.34	−673.10	95.33 ± 0.09
Na_0.09MnO_1.82·0.47H₂O	18.52 ± 0.16 (1,768.78)	3.55 ± 0.01	9.69	187.09 ± 1.35 (8)	154.35 ± 1.13	−60.45 ± 1.49	−83.69 ± 2.40	−656.17	90.88 ± 0.08
K_0.21MnO_1.87·0.49H₂O	34.63 ± 0.44 (3,595.24)	3.53 ± 0.01	11.35	154.25 ± 1.93 (10)	120.47 ± 2.73	−51.23 ± 2.05	−74.40 ± 3.88	−679.98	98.86 ± 0.08
K_0.21MnO_1.90·0.47H₂O	28.74 ± 0.21 (2,991.87)	3.59 ± 0.01	11.55	154.06 ± 1.90 (8)	121.29 ± 2.69	−49.57 ± 2.03	−75.27 ± 3.84	−678.34	97.21 ± 0.08
K_0.21MnO_1.85·0.23H₂O	18.50 ± 0.17 (1,823.77)	3.49 ± 0.01	6.25	137.18 ± 1.88 (8)	121.33 ± 2.66	−54.00 ± 1.99	−74.95 ± 3.81	−603.22	80.82 ± 0.07
K_0.20MnO_1.84·0.13H₂O	15.41 ± 0.10 (1,493.37)	3.48 ± 0.01	4.42	130.86 ± 1.39 (8)	121.91 ± 1.97	−53.46 ± 1.53	−76.23 ± 3.11	−574.89	73.39 ± 0.07
Ca_0.12MnO_1.825·0.81H₂O	97.76 ± 0.87 (10,383.96)	3.53 ± 0.01	15.62	181.29 ± 1.88 (10)	125.71 ± 2.66	−33.63 ± 1.99	−55.44 ± 3.81	−817.68	115.95 ± 0.11
Ca_0.11MnO_1.79·0.73H₂O	55.42 ± 0.51 (5,653.72)	3.47 ± 0.01	11.92	177.40 ± 1.73 (8)	127.04 ± 2.45	−37.21 ± 1.83	−57.08 ± 3.58	−777.27	110.21 ± 0.11
Ca_0.12MnO_1.82·0.66H₂O	34.63 ± 0.44 (3,552.24)	3.52 ± 0.01	12.10	174.49 ± 1.29 (8)	128.80 ± 1.83	−37.66 ± 1.44	−58.86 ± 2.98	−770.26	105.49 ± 0.10
Ca_0.12MnO_1.80·0.67H₂O	18.50 ± 0.17 (1,877.27)	3.48 ± 0.01	11.10	175.30 ± 1.19 (8)	128.88 ± 1.69	−39.68 ± 1.33	−59.49 ± 2.85	−765.85	106.35 ± 0.10
K_0.10MnO_1.885·0.43H₂O	234.02 ± 0.77(22,852.59)	3.67 ± 0.01	11.88	124.58 ± 1.88 (10)	94.77 ± 2.66	−1.56 ± 2.02	−29.78 ± 3.81	−648.54	88.91 ± 0.07
K_0.11MnO_1.955·0.41H₂O	150.63 ± 0.16 (14,842.18)	3.80 ± 0.01	12.59	132.71 ± 1.75 (8)	104.38 ± 2.48	−6.49 ± 1.94	−39.39 ± 3.61	−648.44	87.45 ± 0.07
K_0.11MnO_1.96·0.36H₂O	128.05 ± 0.14 (12,503.15)	3.81 ± 0.01	11.69	129.34 ± 1.17 (8)	104.68 ± 1.66	−6.09 ± 1.45	−39.69 ± 2.83	−633.54	83.90 ± 0.07
K_0.10MnO_1.965·0.28H₂O	58.00 ± 0.25 (5,581.71)	3.83 ± 0.01	10.38	128.04 ± 1.01 (8)	109.02 ± 1.44	−7.77 ± 1.34	−43.50 ± 2.64	−610.76	77.75 ± 0.07

Sample compositions are normalized to 1 mol of Mn.

^{^†}

BET surface areas are from the average of two runs.

^{^‡}

TGA total weight loss at 973 K and O₂ corrected to obtain water content. The final oxidation state for the Mn oxides is Mn³⁺ in sodium molybdate at 973 K.

^{^§}

ΔH_ds is measured drop solution enthalpy in which the error is 2 SDs of the mean and the values in parentheses are the mean number of experiments.

^{^¶}

ΔH_ds,corr is drop solution enthalpy corrected for water content.

^{^#}

Formation enthalpy from the oxides (ΔH^o_f-ox), computed as mA^c+O, Mn₂O₃, H₂O, and MnO₂, is without redox enthalpy contributions.

^{^||}

ΔH^o_f-ox* (as mA^c+O, Mn₂O₃, H₂O, and O₂) includes the exothermic oxidation enthalpy.

^**

Standard formation enthalpies from the elements (∆H^o_f) were computed from standard formation enthalpies of simple binary oxides (Mn₂O₃ = −959.0 ± 1.0 kJ/mol and MnO₂ = −520.0 ± 0.7 kJ/mol) (13), and the propagated error is ±2.22 kJ/mol. Auxiliary drop solution enthalpy data, ΔH_ds, used to compute formation enthalpies of the complex Mn oxides, includes ΔH_dsNa₂O = −207.56 ± 4.25 kJ/mol, ΔH_dsK₂O = −318.0 ± 3.1 kJ/mol, and ΔH_dsCa₂O = −90.3 ± 1.8 kJ/mol from (29); ΔH_dsMn₂O₃ = 154.87 ± 1.00 kJ/mol and ΔH_dsMnO₂ = 124.92 ± 1.03 kJ/mol from ref. 13. The heat content of molecular oxygen is 21.84 kJ/mol (29) and of water (starting with liquid) is 69.0 ± 0.1 kJ/mol (29). Standard formation enthalpy (∆H°_f) and standard entropy (S°₂₉₈) of liquid water is −285.8 ± 0.1 kJ/mol and 70.0 ± 0.1 J/mol⋅K (29).

^{^††}

Standard entropy (S°₂₉₈) of molecular oxygen is 205.15 ± 0.01 J/mol⋅K (29). The standard entropy and enthalpy of hydrogen ion in water, S°_(aq,298) = 0 J/mol⋅K (29).