Frost, Ray LeslieCipriano, Ricardo Augusto ScholzLópez, AndrésLana, Cristiano de CarvalhoXi, Yunfei2014-11-182014-11-182014FROST, RAY L. et al. A Raman and infrared spectroscopic analysis of the phosphate mineral wardite NaAl3(PO4)2(OH)4 .2(H2O) from Brazi. Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy, v. 11, p. 1, 2014. Disponível em: <http://www.sciencedirect.com/science/article/pii/S1386142514001942>. Acesso em: 04 set. 2014.1386-1425http://www.repositorio.ufop.br/handle/123456789/3956A wardite mineral sample from Lavra Da Ilha, Minas Gerais, Brazil has been examined by vibrational spectroscopy. The mineral is unusual in that it belongs to a unique symmetry class, namely the tetragonal-trapezohedral group. The structure of wardite contains layers of corner-linked –OH bridged MO6 octahedra stacked along the tetragonal C-axis in a four-layer sequence and linked by PO4 groups. Consequentially not all phosphate units are identical. Two intense Raman bands observed at 995 and 1051 cm^-1 are assigned to the m1 PO4^3- symmetric stretching mode. Intense Raman bands are observed at 605 and 618 cm^-1 with shoulders at 578 and 589 cm^-1 are assigned to the m4 out of plane bending modes of the PO4^3- . The observation of multiple bands supports the concept of non-equivalent phosphate units in the structure. Sharp infrared bands are observed at 3544 and 3611 cm^-1 are attributed to the OH stretching vibrations of the hydroxyl units. Vibrational spectroscopy enables subtle details of the molecular structure of wardite to be determined.en-USWarditeCyrilovitePhosphateHydroxylRaman spectroscopyArtigo publicado em periodicoO periódico Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy concede permissão para depósito deste artigo no Repositório Institucional da UFOP. Número da licença: 3466021138825.https://doi.org/10.1016/j.saa.2014.02.007