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Chemical reactions
4As + 3H2SiO3 🔥→ As2O3 + 2AsH3↑ + 3SiO2

4As + 3H₂SiO₃ 🔥→ As₂O₃ + 2AsH₃↑ + 3SiO₂

Last updated: June 13, 2022

Reaction of arsenic and metasilicic acid: 4AsArsenic + 3H₂SiO₃Metasilicic acid
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As₂O₃Diarsenic trioxide + 2AsH₃↑Arsine + 3SiO₂Silicon dioxide

The reaction of arsenic and metasilicic acid yields diarsenic trioxide, arsine, and silicon dioxide (Other reactions are here). This reaction is an oxidation-reduction reaction and is classified as follows:

Reaction of self redoxing species and acid

Table of contents

Reaction data

Chemical equation

Reaction of arsenic and metasilicic acid: 4AsArsenic + 3H₂SiO₃Metasilicic acid
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As₂O₃Diarsenic trioxide + 2AsH₃↑Arsine + 3SiO₂Silicon dioxide

General equation

Reaction of self redoxing species and acid: Self-redoxing speciesSelf redox agent + AcidNon-redox agent
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ProductOxidation product + ProductReduction product

Oxidation state of each atom

Reaction of arsenic and metasilicic acid

Reactants

Chemical formula	Name	Coefficient	Type	Type in general equation
As	Arsenic	4	–	Self redoxing
H₂SiO₃	Metasilicic acid	3	–	Acid

Products

Chemical formula	Name	Coefficient	Type	Type in general equation
As₂O₃	Diarsenic trioxide	1	Oxidized	–
AsH₃	Arsine	2	Reduced	–
SiO₂	Silicon dioxide	3	–	–

Thermodynamic changes

Changes in standard condition (1)

Reaction of arsenic and metasilicic acid ◆ Δ_rG 268.9 kJ/mol K 0.78 × 10⁻⁴⁷ pK 47.11: 4AsCrystalline solidα, gray, metallic + 3H₂SiO₃Crystalline solid
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⟶
As₂O₃Crystalline solidoctahedral + 2AsH₃↑Gas + 3SiO₂Crystalline solidα-quartz

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	309.2	268.9	136	–
per 1 mol of Arsenic	77.30	67.22	34.0	–
per 1 mol of Metasilicic acid	103.1	89.63	45.3	–
per 1 mol of Diarsenic trioxide	309.2	268.9	136	–
per 1 mol of Arsine	154.6	134.4	68.0	–
per 1 mol of Silicon dioxide	103.1	89.63	45.3	–

Changes in standard condition (2)

Reaction of arsenic and metasilicic acid ◆ Δ_rG 272.6 kJ/mol K 0.17 × 10⁻⁴⁷ pK 47.76: 4AsCrystalline solidα, gray, metallic + 3H₂SiO₃Crystalline solid
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⟶
As₂O₃Crystalline solidoctahedral + 2AsH₃↑Gas + 3SiO₂Crystalline solidα-cristobalite

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	313.6	272.6	138	–
per 1 mol of Arsenic	78.40	68.15	34.5	–
per 1 mol of Metasilicic acid	104.5	90.87	46.0	–
per 1 mol of Diarsenic trioxide	313.6	272.6	138	–
per 1 mol of Arsine	156.8	136.3	69.0	–
per 1 mol of Silicon dioxide	104.5	90.87	46.0	–

Changes in standard condition (3)

Reaction of arsenic and metasilicic acid ◆ Δ_rG 273.1 kJ/mol K 0.14 × 10⁻⁴⁷ pK 47.85: 4AsCrystalline solidα, gray, metallic + 3H₂SiO₃Crystalline solid
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As₂O₃Crystalline solidoctahedral + 2AsH₃↑Gas + 3SiO₂Crystalline solidα-tridymite

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	314.8	273.1	141	–
per 1 mol of Arsenic	78.70	68.28	35.3	–
per 1 mol of Metasilicic acid	104.9	91.03	47.0	–
per 1 mol of Diarsenic trioxide	314.8	273.1	141	–
per 1 mol of Arsine	157.4	136.6	70.5	–
per 1 mol of Silicon dioxide	104.9	91.03	47.0	–

Changes in standard condition (4)

Reaction of arsenic and metasilicic acid ◆ Δ_rG 286.7 kJ/mol K 0.59 × 10⁻⁵⁰ pK 50.23: 4AsCrystalline solidα, gray, metallic + 3H₂SiO₃Crystalline solid
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As₂O₃Crystalline solidoctahedral + 2AsH₃↑Gas + 3SiO₂Amorphous solid

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	331.5	286.7	151	–
per 1 mol of Arsenic	82.88	71.67	37.8	–
per 1 mol of Metasilicic acid	110.5	95.57	50.3	–
per 1 mol of Diarsenic trioxide	331.5	286.7	151	–
per 1 mol of Arsine	165.8	143.3	75.5	–
per 1 mol of Silicon dioxide	110.5	95.57	50.3	–

Changes in standard condition (5)

Reaction of arsenic and metasilicic acid ◆ Δ_rG 268.2 kJ/mol K 0.10 × 10⁻⁴⁶ pK 46.99: 4AsCrystalline solidα, gray, metallic + 3H₂SiO₃Crystalline solid
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⟶
As₂O₃Crystalline solidmonoclinic + 2AsH₃↑Gas + 3SiO₂Crystalline solidα-quartz

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	311.4	268.2	146	–
per 1 mol of Arsenic	77.85	67.05	36.5	–
per 1 mol of Metasilicic acid	103.8	89.40	48.7	–
per 1 mol of Diarsenic trioxide	311.4	268.2	146	–
per 1 mol of Arsine	155.7	134.1	73.0	–
per 1 mol of Silicon dioxide	103.8	89.40	48.7	–

Changes in standard condition (6)

Reaction of arsenic and metasilicic acid ◆ Δ_rG 271.8 kJ/mol K 0.24 × 10⁻⁴⁷ pK 47.62: 4AsCrystalline solidα, gray, metallic + 3H₂SiO₃Crystalline solid
🔥
⟶
As₂O₃Crystalline solidmonoclinic + 2AsH₃↑Gas + 3SiO₂Crystalline solidα-cristobalite

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	315.7	271.8	148	–
per 1 mol of Arsenic	78.92	67.95	37.0	–
per 1 mol of Metasilicic acid	105.2	90.60	49.3	–
per 1 mol of Diarsenic trioxide	315.7	271.8	148	–
per 1 mol of Arsine	157.8	135.9	74.0	–
per 1 mol of Silicon dioxide	105.2	90.60	49.3	–

Changes in standard condition (7)

Reaction of arsenic and metasilicic acid ◆ Δ_rG 272.3 kJ/mol K 0.20 × 10⁻⁴⁷ pK 47.70: 4AsCrystalline solidα, gray, metallic + 3H₂SiO₃Crystalline solid
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⟶
As₂O₃Crystalline solidmonoclinic + 2AsH₃↑Gas + 3SiO₂Crystalline solidα-tridymite

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	317.0	272.3	151	–
per 1 mol of Arsenic	79.25	68.08	37.8	–
per 1 mol of Metasilicic acid	105.7	90.77	50.3	–
per 1 mol of Diarsenic trioxide	317.0	272.3	151	–
per 1 mol of Arsine	158.5	136.2	75.5	–
per 1 mol of Silicon dioxide	105.7	90.77	50.3	–

Changes in standard condition (8)

Reaction of arsenic and metasilicic acid ◆ Δ_rG 286.0 kJ/mol K 0.79 × 10⁻⁵⁰ pK 50.11: 4AsCrystalline solidα, gray, metallic + 3H₂SiO₃Crystalline solid
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⟶
As₂O₃Crystalline solidmonoclinic + 2AsH₃↑Gas + 3SiO₂Amorphous solid

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	333.7	286.0	161	–
per 1 mol of Arsenic	83.42	71.50	40.3	–
per 1 mol of Metasilicic acid	111.2	95.33	53.7	–
per 1 mol of Diarsenic trioxide	333.7	286.0	161	–
per 1 mol of Arsine	166.8	143.0	80.5	–
per 1 mol of Silicon dioxide	111.2	95.33	53.7	–

Changes in standard condition (9)

Reaction of arsenic and metasilicic acid: 4AsCrystalline solidγ, yellow, cubic + 3H₂SiO₃Crystalline solid
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⟶
As₂O₃Crystalline solidoctahedral + 2AsH₃↑Gas + 3SiO₂Crystalline solidα-quartz

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	250.8	–	–	–
per 1 mol of Arsenic	62.70	–	–	–
per 1 mol of Metasilicic acid	83.60	–	–	–
per 1 mol of Diarsenic trioxide	250.8	–	–	–
per 1 mol of Arsine	125.4	–	–	–
per 1 mol of Silicon dioxide	83.60	–	–	–

Changes in standard condition (10)

Reaction of arsenic and metasilicic acid: 4AsCrystalline solidγ, yellow, cubic + 3H₂SiO₃Crystalline solid
🔥
⟶
As₂O₃Crystalline solidoctahedral + 2AsH₃↑Gas + 3SiO₂Crystalline solidα-cristobalite

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	255.2	–	–	–
per 1 mol of Arsenic	63.80	–	–	–
per 1 mol of Metasilicic acid	85.07	–	–	–
per 1 mol of Diarsenic trioxide	255.2	–	–	–
per 1 mol of Arsine	127.6	–	–	–
per 1 mol of Silicon dioxide	85.07	–	–	–

Changes in standard condition (11)

Reaction of arsenic and metasilicic acid: 4AsCrystalline solidγ, yellow, cubic + 3H₂SiO₃Crystalline solid
🔥
⟶
As₂O₃Crystalline solidoctahedral + 2AsH₃↑Gas + 3SiO₂Crystalline solidα-tridymite

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	256.4	–	–	–
per 1 mol of Arsenic	64.10	–	–	–
per 1 mol of Metasilicic acid	85.47	–	–	–
per 1 mol of Diarsenic trioxide	256.4	–	–	–
per 1 mol of Arsine	128.2	–	–	–
per 1 mol of Silicon dioxide	85.47	–	–	–

Changes in standard condition (12)

Reaction of arsenic and metasilicic acid: 4AsCrystalline solidγ, yellow, cubic + 3H₂SiO₃Crystalline solid
🔥
⟶
As₂O₃Crystalline solidoctahedral + 2AsH₃↑Gas + 3SiO₂Amorphous solid

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	273.1	–	–	–
per 1 mol of Arsenic	68.28	–	–	–
per 1 mol of Metasilicic acid	91.03	–	–	–
per 1 mol of Diarsenic trioxide	273.1	–	–	–
per 1 mol of Arsine	136.6	–	–	–
per 1 mol of Silicon dioxide	91.03	–	–	–

Changes in standard condition (13)

Reaction of arsenic and metasilicic acid: 4AsCrystalline solidγ, yellow, cubic + 3H₂SiO₃Crystalline solid
🔥
⟶
As₂O₃Crystalline solidmonoclinic + 2AsH₃↑Gas + 3SiO₂Crystalline solidα-quartz

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	253.0	–	–	–
per 1 mol of Arsenic	63.25	–	–	–
per 1 mol of Metasilicic acid	84.33	–	–	–
per 1 mol of Diarsenic trioxide	253.0	–	–	–
per 1 mol of Arsine	126.5	–	–	–
per 1 mol of Silicon dioxide	84.33	–	–	–

Changes in standard condition (14)

Reaction of arsenic and metasilicic acid: 4AsCrystalline solidγ, yellow, cubic + 3H₂SiO₃Crystalline solid
🔥
⟶
As₂O₃Crystalline solidmonoclinic + 2AsH₃↑Gas + 3SiO₂Crystalline solidα-cristobalite

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	257.3	–	–	–
per 1 mol of Arsenic	64.33	–	–	–
per 1 mol of Metasilicic acid	85.77	–	–	–
per 1 mol of Diarsenic trioxide	257.3	–	–	–
per 1 mol of Arsine	128.7	–	–	–
per 1 mol of Silicon dioxide	85.77	–	–	–

Changes in standard condition (15)

Reaction of arsenic and metasilicic acid: 4AsCrystalline solidγ, yellow, cubic + 3H₂SiO₃Crystalline solid
🔥
⟶
As₂O₃Crystalline solidmonoclinic + 2AsH₃↑Gas + 3SiO₂Crystalline solidα-tridymite

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	258.6	–	–	–
per 1 mol of Arsenic	64.65	–	–	–
per 1 mol of Metasilicic acid	86.20	–	–	–
per 1 mol of Diarsenic trioxide	258.6	–	–	–
per 1 mol of Arsine	129.3	–	–	–
per 1 mol of Silicon dioxide	86.20	–	–	–

Changes in standard condition (16)

Reaction of arsenic and metasilicic acid: 4AsCrystalline solidγ, yellow, cubic + 3H₂SiO₃Crystalline solid
🔥
⟶
As₂O₃Crystalline solidmonoclinic + 2AsH₃↑Gas + 3SiO₂Amorphous solid

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	275.3	–	–	–
per 1 mol of Arsenic	68.83	–	–	–
per 1 mol of Metasilicic acid	91.77	–	–	–
per 1 mol of Diarsenic trioxide	275.3	–	–	–
per 1 mol of Arsine	137.7	–	–	–
per 1 mol of Silicon dioxide	91.77	–	–	–

Changes in standard condition (17)

Reaction of arsenic and metasilicic acid: 4AsAmorphous solidβ + 3H₂SiO₃Crystalline solid
🔥
⟶
As₂O₃Crystalline solidoctahedral + 2AsH₃↑Gas + 3SiO₂Crystalline solidα-quartz

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	292.4	–	–	–
per 1 mol of Arsenic	73.10	–	–	–
per 1 mol of Metasilicic acid	97.47	–	–	–
per 1 mol of Diarsenic trioxide	292.4	–	–	–
per 1 mol of Arsine	146.2	–	–	–
per 1 mol of Silicon dioxide	97.47	–	–	–

Changes in standard condition (18)

Reaction of arsenic and metasilicic acid: 4AsAmorphous solidβ + 3H₂SiO₃Crystalline solid
🔥
⟶
As₂O₃Crystalline solidoctahedral + 2AsH₃↑Gas + 3SiO₂Crystalline solidα-cristobalite

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	296.8	–	–	–
per 1 mol of Arsenic	74.20	–	–	–
per 1 mol of Metasilicic acid	98.93	–	–	–
per 1 mol of Diarsenic trioxide	296.8	–	–	–
per 1 mol of Arsine	148.4	–	–	–
per 1 mol of Silicon dioxide	98.93	–	–	–

Changes in standard condition (19)

Reaction of arsenic and metasilicic acid: 4AsAmorphous solidβ + 3H₂SiO₃Crystalline solid
🔥
⟶
As₂O₃Crystalline solidoctahedral + 2AsH₃↑Gas + 3SiO₂Crystalline solidα-tridymite

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	298.0	–	–	–
per 1 mol of Arsenic	74.50	–	–	–
per 1 mol of Metasilicic acid	99.33	–	–	–
per 1 mol of Diarsenic trioxide	298.0	–	–	–
per 1 mol of Arsine	149.0	–	–	–
per 1 mol of Silicon dioxide	99.33	–	–	–

Changes in standard condition (20)

Reaction of arsenic and metasilicic acid: 4AsAmorphous solidβ + 3H₂SiO₃Crystalline solid
🔥
⟶
As₂O₃Crystalline solidoctahedral + 2AsH₃↑Gas + 3SiO₂Amorphous solid

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	314.7	–	–	–
per 1 mol of Arsenic	78.67	–	–	–
per 1 mol of Metasilicic acid	104.9	–	–	–
per 1 mol of Diarsenic trioxide	314.7	–	–	–
per 1 mol of Arsine	157.3	–	–	–
per 1 mol of Silicon dioxide	104.9	–	–	–

Changes in standard condition (21)

Reaction of arsenic and metasilicic acid: 4AsAmorphous solidβ + 3H₂SiO₃Crystalline solid
🔥
⟶
As₂O₃Crystalline solidmonoclinic + 2AsH₃↑Gas + 3SiO₂Crystalline solidα-quartz

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	294.6	–	–	–
per 1 mol of Arsenic	73.65	–	–	–
per 1 mol of Metasilicic acid	98.20	–	–	–
per 1 mol of Diarsenic trioxide	294.6	–	–	–
per 1 mol of Arsine	147.3	–	–	–
per 1 mol of Silicon dioxide	98.20	–	–	–

Changes in standard condition (22)

Reaction of arsenic and metasilicic acid: 4AsAmorphous solidβ + 3H₂SiO₃Crystalline solid
🔥
⟶
As₂O₃Crystalline solidmonoclinic + 2AsH₃↑Gas + 3SiO₂Crystalline solidα-cristobalite

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	298.9	–	–	–
per 1 mol of Arsenic	74.72	–	–	–
per 1 mol of Metasilicic acid	99.63	–	–	–
per 1 mol of Diarsenic trioxide	298.9	–	–	–
per 1 mol of Arsine	149.4	–	–	–
per 1 mol of Silicon dioxide	99.63	–	–	–

Changes in standard condition (23)

Reaction of arsenic and metasilicic acid: 4AsAmorphous solidβ + 3H₂SiO₃Crystalline solid
🔥
⟶
As₂O₃Crystalline solidmonoclinic + 2AsH₃↑Gas + 3SiO₂Crystalline solidα-tridymite

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	300.2	–	–	–
per 1 mol of Arsenic	75.05	–	–	–
per 1 mol of Metasilicic acid	100.1	–	–	–
per 1 mol of Diarsenic trioxide	300.2	–	–	–
per 1 mol of Arsine	150.1	–	–	–
per 1 mol of Silicon dioxide	100.1	–	–	–

Changes in standard condition (24)

Reaction of arsenic and metasilicic acid: 4AsAmorphous solidβ + 3H₂SiO₃Crystalline solid
🔥
⟶
As₂O₃Crystalline solidmonoclinic + 2AsH₃↑Gas + 3SiO₂Amorphous solid

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	316.9	–	–	–
per 1 mol of Arsenic	79.22	–	–	–
per 1 mol of Metasilicic acid	105.6	–	–	–
per 1 mol of Diarsenic trioxide	316.9	–	–	–
per 1 mol of Arsine	158.4	–	–	–
per 1 mol of Silicon dioxide	105.6	–	–	–

Changes in aqueous solution

Reaction of arsenic and metasilicic acid: 4AsCrystalline solidα, gray, metallic + 3H₂SiO₃Un-ionized aqueous solution
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As₂O₃Aqueous solution + 2AsH₃↑Gas + 3SiO₂Un-ionized aqueous solution

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	363.5	–	–	–
per 1 mol of Arsenic	90.88	–	–	–
per 1 mol of Metasilicic acid	121.2	–	–	–
per 1 mol of Diarsenic trioxide	363.5	–	–	–
per 1 mol of Arsine	181.8	–	–	–
per 1 mol of Silicon dioxide	121.2	–	–	–

Thermodynamic data of reactants

Chemical formula	Standard enthalpy of formation Δ_fH° kJ · mol⁻¹	Standard Gibbs energy of formation Δ_fG° kJ · mol⁻¹	Standard molar entropy S° J · K⁻¹ · mol⁻¹	Standard molar heat capacity at constant pressure C_p° J · K⁻¹ · mol⁻¹
As (cr) α, gray, metallic	0^[1]	0^[1]	35.1^[1]	24.64^[1]
As (cr) γ, yellow, cubic	14.6^[1]	–	–	–
As (am) β	4.2^[1]	–	–	–
As (g)	302.5^[1]	261.0^[1]	174.21^[1]	20.786^[1]
H₂SiO₃ (cr)	-1188.7^[1]	-1092.4^[1]	134^[1]	–
H₂SiO₃ (ao)	-1182.8^[1]	-1079.4^[1]	109^[1]	–

* (cr):Crystalline solid, (am):Amorphous solid, (g):Gas, (ao):Un-ionized aqueous solution

Thermodynamic data of products

Chemical formula	Standard enthalpy of formation Δ_fH° kJ · mol⁻¹	Standard Gibbs energy of formation Δ_fG° kJ · mol⁻¹	Standard molar entropy S° J · K⁻¹ · mol⁻¹	Standard molar heat capacity at constant pressure C_p° J · K⁻¹ · mol⁻¹
As₂O₃ (cr) octahedral	-656.97^[1]	-576.22^[1]	107.1^[1]	95.65^[1]
As₂O₃ (cr) monoclinic	-654.8^[1]	-576.97^[1]	117^[1]	–
As₂O₃ (g)	-604.6^[1]	-548.9^[1]	191^[1]	–
As₂O₃ (aq)	-626.8^[1]	–	–	–
AsH₃ (g)	66.44^[1]	68.93^[1]	222.78^[1]	38.07^[1]
SiO₂ (cr) α-quartz	-910.94^[1]	-856.64^[1]	41.84^[1]	44.43^[1]
SiO₂ (cr) α-cristobalite	-909.48^[1]	-855.43^[1]	42.68^[1]	44.18^[1]
SiO₂ (cr) α-tridymite	-909.06^[1]	-855.26^[1]	43.5^[1]	44.60^[1]
SiO₂ (am)	-903.49^[1]	-850.70^[1]	46.9^[1]	44.4^[1]
SiO₂ (g)	-322^[1]	–	–	–
SiO₂ (ao)	-897.0^[1]	–	–	–

* (cr):Crystalline solid, (g):Gas, (aq):Aqueous solution, (am):Amorphous solid, (ao):Un-ionized aqueous solution

References

List of references

1
Janiel J. Reed (1989)
The NBS Tables of Chemical Thermodynamic Properties: Selected Values for Inorganic and C1 and C2 Organic Substances in SI Units
https://doi.org/10.18434/M32124
National Institute of Standards and Technology (NIST)
Citation list

Δ_rG	268.9 kJ/mol
K	0.78 × 10⁻⁴⁷
pK	47.11

Δ_rG	272.6 kJ/mol
K	0.17 × 10⁻⁴⁷
pK	47.76

Δ_rG	273.1 kJ/mol
K	0.14 × 10⁻⁴⁷
pK	47.85

Δ_rG	286.7 kJ/mol
K	0.59 × 10⁻⁵⁰
pK	50.23

4As + 3H2SiO3 🔥→ As2O3 + 2AsH3↑ + 3SiO2

Reaction data

Chemical equation

General equation

Oxidation state of each atom

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Products

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Changes in standard condition (1)

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Changes in standard condition (24)

Changes in aqueous solution

Thermodynamic data of reactants

Thermodynamic data of products

References

List of references

Related reactions

Reactions with same reactants

Related categories

Type of reaction

General equation

Reactant

Product

4As + 3H₂SiO₃ 🔥→ As₂O₃ + 2AsH₃↑ + 3SiO₂