Whelanite Ca5Cu2(OH)2CO3,Si6O17•4H2O – A vibrational spectroscopic study
Whelanite Ca5Cu2(OH)2CO3,Si6O17•4H2O is a hydrated hydroxy mixed anion compound with both silicate and carbonate anions in the formula. The structural characterisation of the mineral whelanite remains incomplete. Whelanite is probably a neosilicate with Cu2+ in square planar coordination.
Two Raman bands at 1070 and 1094 cm-1 are assigned to the ν1 symmetric stretching modes of the CO32- units. The observation of two symmetric stretching modes supports the concept of two non-equivalent CO32- units in the whelanite structure. The intense sharp Raman band at 1006 cm-1 is assigned to the ν1 (A1g) symmetric stretching vibration of the Si6O17 units. The splitting of the ν3 vibrational mode offers support to the concept that the SiO4 tetrahedron in whelanite is strongly distorted. A very intense Raman band observed at 666 cm-1 with a shoulder at 697 cm-1 is assigned to the ν4 vibrational modes. Intense Raman bands at 3534, 3556, 3550 and 3595 cm-1 are assigned to the stretching vibrations of the OH units. Low intensity Raman bands at 2910, 3187 and 3453 cm-1 are assigned to water stretching modes. Thus, vibrational spectroscopy has been used to characterise the molecular structure of whelanite. Whelanite is a mineral that could be conceived as a healing mineral
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|Item Type:||Journal Article|
|Keywords:||whelanite, healing mineral, chrysocolla, silicate, Raman spectroscopy, dioptase|
|Subjects:||Australian and New Zealand Standard Research Classification > CHEMICAL SCIENCE (030000) > PHYSICAL CHEMISTRY (INCL. STRUCTURAL) (030600) > Structural Chemistry and Spectroscopy (030606)|
|Divisions:||Current > Schools > School of Chemistry, Physics & Mechanical Engineering
Current > QUT Faculties and Divisions > Science & Engineering Faculty
|Copyright Owner:||Copyright 2012 Elsevier B.V.|
|Copyright Statement:||NOTICE: this is the author’s version of a work that was accepted for publication in Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy, [VOL 91, (2012)] DOI 10.1016/j.saa.2012.02.003|
|Deposited On:||07 Mar 2012 05:02|
|Last Modified:||10 Sep 2013 08:22|
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