Vibrational spectroscopy of the multianion mineral gartrellite from the Anticline Deposit, Ashburton Downs, Western Australia

• We have undertaken a study of the mineral gartrellite.
• We have characterised the arsenate and sulphate anions in the mineral gartrellite.
• The fundamental internal modes in the spectra are related to the structure of the mineral gartrellite.
• Gartrellite minerals are characterised by typical spectra of the AsO43- units.

The multianion mineral gartrellite PbCu(Fe3+,Cu)(AsO4)2(OH,H2O)2 has been studied by a combination of Raman and infrared spectroscopy. The molecular structure of gartrellite is assessed. Gartrellite is one of the tsumcorite mineral group based upon arsenate and/or sulphate anions. Crystal symmetry is either triclinic in the case of an ordered occupation of two cationic sites, triclinic due to ordering of the H bonds in the case of species with two water molecules per formula unit, or monoclinic in the other cases. Characteristic Raman spectra of the mineral gartrellite enable the assignment of the bands to specific vibrational modes. These spectra are related to the structure of gartrellite. The position of the hydroxyl and water stretching vibrations are related to the strength of the hydrogen bond formed between the OH unit and the AsO43- anion.

Figure optionsDownload as PowerPoint slide