کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1230591 1495240 2014 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Phase transformation of calcium oxalate dihydrate–monohydrate: Effects of relative humidity and new spectroscopic data
ترجمه فارسی عنوان
تبدیل فاز دی هیدرات اگزالات کلسیم مونوهیدرات: تاثیر رطوبت نسبی و اطلاعات طیف سنجی جدید
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آنالیزی یا شیمی تجزیه
چکیده انگلیسی


• We study the vibrational properties of monohydrate and dihydrate phases of calcium oxalate.
• We investigate the phase transformation of calcium oxalate dihydrate.
• We report a re-investigation of the vibrational spectra (Raman and IR) of whewellite.
• X-ray diffraction show the influence of relative humidity on the stability of weddellite.
• The new data achieved will provide essential information in medical and Cultural Heritage fields.

New data on vibrational properties of calcium oxalates and their controversial transformation mechanism are presented. We have focused on whewellite (CaC2O4·H2O) and weddellite [CaC2O4·(2 + x) H2O], the most common phases of calcium oxalate; these compounds occur in many organisms, in kidney stones and in particular kinds of films found on the surface of many works of art. Low temperature experiments carried out by Fourier transform infrared spectroscopy have highlighted both the high structural order in the crystalline state of whewellite and the disordered distribution of the zeolitic water molecules in weddellite. The synthesised nanocrystals of weddellite have been kept under different hygrometric conditions in order to study, by X-ray powder diffraction, the role of “external” water molecules on their stability. Moreover, in order to identify the different kinds of water molecules, a re-investigation, supported by quantum chemical calculations, of the observed vibrational spectra (IR and Raman) of whewellite has been conducted.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy - Volume 128, 15 July 2014, Pages 413–419
نویسندگان
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