Atacamite

Formula : Cu₄Cl₂(OH)₆

Family:

Space group:

Orthorhombic - Dipyramidal HM symbol (2/m 2/m 2/m) Space Group: Pnma

High temperature:

low temperature (surface)

Geological context:

secondary mineral of oxidized copper mineralizations, especially in arid, saline conditions; common in the oxidized portions of black smoker deposits

Dernière mise à jour le 25.01.2021

Individual properties (298.15 K)

M g·mol^-1	V° cm³·mol^-1	ΔGº_f J·mol^-1	ΔHº_f J·mol^-1	Sº J·mol^-1·k^-1	C_P J·mol^-1·K^-1
427.133	113.599 (Ref.: 90rob/cam) Roberts, Willard L., Campbell, Thomas J., and Rapp, George R.: Encyclopedia of Minerals. (Van Nostrand Reinhold Co., 2nd ed., 1990)	-1339955 (Ref.: 00pui) Puigdomenech, I., 2000. Thermodynamic data for copper: implications for the corrosion of copper under repository conditions, SKB report. SKB/Swedish Nuclear Fuel and Waste Management, p. 96.	-1646336 (Ref.: Internal calculation)	335.570 (Ref.: 00pui) Puigdomenech, I., 2000. Thermodynamic data for copper: implications for the corrosion of copper under repository conditions, SKB report. SKB/Swedish Nuclear Fuel and Waste Management, p. 96.	349.33 (Ref.: 00pui) Puigdomenech, I., 2000. Thermodynamic data for copper: implications for the corrosion of copper under repository conditions, SKB report. SKB/Swedish Nuclear Fuel and Waste Management, p. 96.

C_P(T) = a + b·T + ·c·T^-2 (T in Kelvin)

a J·mol^-1·K^-1	*b 10³** J·mol^-1·K^-2	*c 10^-5** J·K·mol^-1	Maier Kelley Ref.
312.62	134.86	-3.11	(Ref.: 00pui) Puigdomenech, I., 2000. Thermodynamic data for copper: implications for the corrosion of copper under repository conditions, SKB report. SKB/Swedish Nuclear Fuel and Waste Management, p. 96.

Reaction properties

Atacamite + 6H⁺ ⇌ 2Cl^- + 4Cu⁺² + 6H₂O

298.15 K, 1 bar log₁₀K: 14.93 ΔH°_r:-142094 J·mol^-1

T(°C)	0	25	60	100	150	200	250	300
log₁₀K	17.16	14.93	12.27	9.78	7.16	4.82	2.51	-0.10

log₁₀K(T) = A + B·T + C·T^-1 + D·log₁₀(T) + E·T⁻² (T in Kelvin)

A	B	C	D	E
-2588.464256	-0.406247	145533.453767	939.403364	-7831614.363933