Titre du document / Document title

THERMOGRAVIMETRIC ANALYSIS OF WHEATLEYITE Na₂Cu²⁺(C₂O₄)₂·2H₂O

Auteur(s) / Author(s)

FROST R. L. ⁽¹⁾ ; LOCKE A. ⁽¹⁾ ; MARTENS W. N. ⁽¹⁾ ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

⁽¹⁾ Inorganic Materials Research Program, Queensland University of Technology, 2 George Street, Brisbane, GPO Box 2434, Queensland 4001, AUSTRALIE

Résumé / Abstract

Evidence for the existence of primitive life forms such as lichens and fungi can be based upon the formation of oxalates. These oxalates form as a film like deposit on rocks and other host matrices. The anhydrous oxalate mineral moolooite CuC₂O₄ as the natural copper(II) oxalate mineral is a classic example. Another example of a natural oxalate is the mineral wheatleyite Na₂Cu²⁺(C₂O₄)₂·2H₂O. High resolution thermogravimetry coupled to evolved gas mass spectrometry shows decomposition of wheatleyite at 255°C. Two higher temperature mass losses are observed at 324 and 349°C. Higher temperature mass losses are observed at 819, 833 and 857°C. These mass losses as confirmed by mass spectrometry are attributed to the decomposition of tennerite CuO. In comparison the thermal decomposition of moolooite takes place at 260°C. Evolved gas mass spectrometry for moolooite shows the gas lost at this temperature is carbon dioxide. No water evolution was observed, thus indicating the moolooite is the anhydrous copper(II) oxalate as compared to the synthetic compound which is the dihydrate.

Revue / Journal Title

Journal of thermal analysis and calorimetry   ISSN 1388-6150 

Source / Source

2008, vol. 93, n^o3, pp. 993-997 [5 page(s) (article)] (58 ref.)

Langue / Language

Anglais

Editeur / Publisher

Springer, Dordrecht, PAYS-BAS  (1998) (Revue)

Mots-clés anglais / English Keywords

Transition metal Complexes ; Evolved gas analysis ; Gas release ; Gas analysis ; Thermal analysis ; X ray diffraction ; Thermal stability ; Alkali metal Complexes ; Sodium Complexes ; Copper Complexes ; Raman spectrometry ; Oxalate ; High resolution ; Mass spectrometry ; Copper II Oxalate ; Thermogravimetry ;

Mots-clés français / French Keywords

Métal transition Complexe ; Analyse gaz dégagé ; Moolooite ; Dégagement gazeux ; Analyse gaz ; Analyse thermique ; Diffraction RX ; Stabilité thermique ; Métal alcalin Complexe ; Sodium Complexe ; Cuivre Complexe ; Spectrométrie Raman ; Oxalate ; Haute résolution ; Spectrométrie masse ; Cuivre II Oxalate ; Thermogravimétrie ;

Mots-clés espagnols / Spanish Keywords

Metal transición Complejo ; Desprendimiento gaseoso ; Análisis gas ; Análisis térmico ; Difracción RX ; Estabilidad térmica ; Metal alcalino Complejo ; Sodio Complejo ; Cobre Complejo ; Espectrometría Raman ; Oxalato ; Alta resolucion ; Espectrometría masa ; Cobre II Oxalato ; Termogravimetría ;

Mots-clés d'auteur / Author Keywords

copper(II) oxalate ; evolved gas mass spectrometry ; high resolution thermogravimetry ; moolooite ; oxalate ; Roman spectroscopy ; wheatleyite ;

Localisation / Location

INIST-CNRS, Cote INIST : 6367, 35400019654269.0530