Vibrational spectroscopic characterization of the phosphate mineral kulanite Ba(Fe(2+),Mn(2+),Mg)2(Al,Fe(3+))2(PO4)3(OH)3.
The mineral kulanite BaFe2Al2(PO4)3(OH)3, a barium iron aluminum phosphate, has been studied by using a combination of electron microscopy and vibrational spectroscopy. Scanning electron microscopy with EDX shows the mineral is homogenous with no other phases present. The Raman spectrum is dominated by an intense band at 1022cm(-1) assigned to the PO4(3-)ν1 symmetric stretching mode. Low intensity Raman bands at 1076, 1110, 1146, 1182cm(-1) are attributed to the PO4(3-)ν3 antisymmetric stretching vibrations. The infrared spectrum shows a complex spectral profile with overlapping bands. Multiple phosphate bending vibrations supports the concept of a reduction in symmetry of the phosphate anion. Raman spectrum at 3211, 3513 and 3533cm(-1) are assigned to the stretching vibrations of the OH units. Vibrational spectroscopy enables aspects on the molecular structure of kulanite to be assessed.
A vibrational spectroscopic study of the phosphate mineral lulzacite Sr(2)Fe(2+)(Fe(2+),Mg)(2)Al(4)(PO(4))(4)(OH)(10).
The mineral lulzacite from Saint-Aubin des Chateaux mine, France, with theoretical formula Sr(2)Fe(2+)(Fe(2+),Mg)(2)Al(4)(PO(4))(4)(OH)(10) has been studied using a combination of electron microscopy with EDX and vibrational spectroscopic techniques. Chemical analysis shows a Sr, Fe, Al phosphate with minor amounts of Ga, Ba and Mg. Raman spectroscopy identifies an intense band at 990cm(-1) with an additional band at 1011cm(-1). These bands are attributed to the PO4(3-)ν1 symmetric stretching mode. The ν3 antisymmetric stretching modes are observed by a large number of Raman bands. The Raman bands at 1034, 1051, 1058, 1069 and 1084 together with the Raman bands at 1098, 1116, 1133, 1155 and 1174cm(-1) are assigned to the ν3 antisymmetric stretching vibrations of PO4(3-) and the HOPO3(2-) units. The observation of these multiple Raman bands in the symmetric and antisymmetric stretching region gives credence to the concept that both phosphate and hydrogen phosphate units exist in the structure of lulzacite. The series of Raman bands at 567, 582, 601, 644, 661, 673 and 687cm(-1) are assigned to the PO4(3-)ν2 bending modes. The series of Raman bands at 437, 468, 478, 491, 503cm(-1) are attributed to the PO4(3-) and HOPO3(2-)ν4 bending modes. No Raman bands of lulzacite which could be attributed to the hydroxyl stretching unit were observed. Infrared bands at 3511 and 3359cm(-1) are ascribed to the OH stretching vibration of the OH units. Very broad bands at 3022 and 3299cm(-1) are attributed to the OH stretching vibrations of water. Vibrational spectroscopy offers insights into the molecular structure of the phosphate mineral lulzacite.
Occupational risks of (meth)acrylate compounds in embedding media for electron microscopy
(Meth)acrylates are the main constituents of embedding media widely used in electron microscopy research for low‐temperature embedding of biological tissue. (Meth)acrylates toxicology is still incompletely understood and therefore an estimation of health hazards involved in handling must be inaccurate. (Meth)acrylate monomers are known to be harmful to skin and other tissues and may sensitize workers. Since low‐temperature electron microscopy techniques have gained popularity in research laboratories, it is important to establish safety rules for handling the (meth)acrylate‐containing solutions.