The stability of onoratoite, Sb8O11Cl2, in the supergene environment

Adam J. Roper; Peter Leverett; Timothy D. Murphy; Peter A. Williams

doi:10.1180/minmag.2014.078.7.10

The stability of onoratoite, Sb₈O₁₁Cl₂, in the supergene environment

Adam J. Roper, Peter Leverett, Timothy D. Murphy, Peter A. Williams

Research output: Contribution to journal › Article › peer-review

4 Citations (Scopus)

Abstract

Synthesis and solubility studies of onoratoite have been undertaken to determine the role of this rare secondary phase in the immobilization of Sb and the conditions responsible for its formation in the supergene zone. Solubility studies were undertaken at 298.15 K. A value of ΔG ^θ _f(Sb₈O₁₁Cl₂, s, 298.15 K) =-2576 ±12 kJ mol^-1 was derived. Calculations involving sénarmontite, Sb₂O₃, klebelsbergite, Sb₄O₄SO₄(OH)₂ and schafarzikite, FeSb₂O₄, show that onoratoite is a thermodynamically stable phase only at negligible activities of SO₄^2-(aq) and low activities of Fe²⁺(aq), at low pH and very high activities of Cl^-(aq). This explains why onoratoite is such a rare secondary phase and why it cannot exert any significant influence on the dispersion of Sb in the supergene environment.

Original language	English
Pages (from-to)	1671-1675
Number of pages	5
Journal	Mineralogical Magazine
Volume	78
Issue number	7
DOIs	https://doi.org/10.1180/minmag.2014.078.7.10
Publication status	Published - Dec 2014
Externally published	Yes

Keywords

onoratoite
antimony oxychloride
solubility
stability
chemical mineralogy
supergene zone

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10.1180/minmag.2014.078.7.10

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title = "The stability of onoratoite, Sb8O11Cl2, in the supergene environment",

abstract = "Synthesis and solubility studies of onoratoite have been undertaken to determine the role of this rare secondary phase in the immobilization of Sb and the conditions responsible for its formation in the supergene zone. Solubility studies were undertaken at 298.15 K. A value of ΔG θ f(Sb8O11Cl2, s, 298.15 K) =-2576 ±12 kJ mol-1 was derived. Calculations involving s{\'e}narmontite, Sb2O3, klebelsbergite, Sb4O4SO4(OH)2 and schafarzikite, FeSb2O4, show that onoratoite is a thermodynamically stable phase only at negligible activities of SO42-(aq) and low activities of Fe2+(aq), at low pH and very high activities of Cl-(aq). This explains why onoratoite is such a rare secondary phase and why it cannot exert any significant influence on the dispersion of Sb in the supergene environment.",

keywords = "onoratoite, antimony oxychloride, solubility, stability, chemical mineralogy, supergene zone",

author = "Roper, {Adam J.} and Peter Leverett and Murphy, {Timothy D.} and Williams, {Peter A.}",

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AU - Roper, Adam J.

AU - Leverett, Peter

AU - Murphy, Timothy D.

AU - Williams, Peter A.

PY - 2014/12

Y1 - 2014/12

N2 - Synthesis and solubility studies of onoratoite have been undertaken to determine the role of this rare secondary phase in the immobilization of Sb and the conditions responsible for its formation in the supergene zone. Solubility studies were undertaken at 298.15 K. A value of ΔG θ f(Sb8O11Cl2, s, 298.15 K) =-2576 ±12 kJ mol-1 was derived. Calculations involving sénarmontite, Sb2O3, klebelsbergite, Sb4O4SO4(OH)2 and schafarzikite, FeSb2O4, show that onoratoite is a thermodynamically stable phase only at negligible activities of SO42-(aq) and low activities of Fe2+(aq), at low pH and very high activities of Cl-(aq). This explains why onoratoite is such a rare secondary phase and why it cannot exert any significant influence on the dispersion of Sb in the supergene environment.

AB - Synthesis and solubility studies of onoratoite have been undertaken to determine the role of this rare secondary phase in the immobilization of Sb and the conditions responsible for its formation in the supergene zone. Solubility studies were undertaken at 298.15 K. A value of ΔG θ f(Sb8O11Cl2, s, 298.15 K) =-2576 ±12 kJ mol-1 was derived. Calculations involving sénarmontite, Sb2O3, klebelsbergite, Sb4O4SO4(OH)2 and schafarzikite, FeSb2O4, show that onoratoite is a thermodynamically stable phase only at negligible activities of SO42-(aq) and low activities of Fe2+(aq), at low pH and very high activities of Cl-(aq). This explains why onoratoite is such a rare secondary phase and why it cannot exert any significant influence on the dispersion of Sb in the supergene environment.

KW - onoratoite

KW - antimony oxychloride

KW - solubility

KW - stability

KW - chemical mineralogy

KW - supergene zone

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VL - 78

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JO - Mineralogical Magazine

JF - Mineralogical Magazine

IS - 7

ER -

The stability of onoratoite, Sb₈O₁₁Cl₂, in the supergene environment

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