Donate now to keep alive!Help|Log In|Register|
Home PageMindat NewsThe Mindat ManualHistory of MindatCopyright StatusManagement TeamContact UsAdvertise on Mindat
Donate to MindatSponsor a PageSponsored PagesTop Available PagesMindat AdvertisersAdvertise on Mindat
What is a mineral?The most common minerals on earthMineral PhotographyThe Elements and their MineralsGeological TimeMineral Evolution
Minerals by PropertiesMinerals by ChemistryAdvanced Locality SearchRandom MineralRandom LocalitySearch by minIDLocalities Near MeSearch ArticlesSearch GlossaryMore Search Options
Search For:
Mineral Name:
Locality Name:
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportCoordinate Completion ReportAdd Glossary Item
StatisticsThe ElementsMember ListBooks & MagazinesMineral MuseumsMineral Shows & EventsThe Mindat DirectoryDevice Settings
Photo SearchPhoto GalleriesNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day Gallery

Lithiotantite: refined crystal structure

Posted by Marco E. Ciriotti  
Marco E. Ciriotti April 28, 2012 10:08AM
▪ Menezes Filho, L.A.D., Yang, H., Downs, R.T., Chaves, M.L.S.C., Persiano, A.C. (2012): Lithiotantite, ideally LiTa3O8. Acta Crystallographica, E68, i27-i28.

Lithiotantite (lithium tritantalum octaoxide) and lithiowodginite are natural dimorphs of LiTa3O8, corresponding to the laboratory-synthesized L-LiTa3O8 (low-temperature form) and M-LiTa3O8 (intermediate-temperature form) phases, respectively. Based on single-crystal X-ray diffraction data, this study presents the first structure determination of lithiotantite from a new locality, the Murundu mine, Jenipapo District, Itinga, Minas Gerais, Brazil. Lithiotantite is isotypic with LiNb3O8 and its structure is composed of a slightly distorted hexagonal close-packed array of O atoms stacked in the <-101> direction, with the metal atoms occupying half of the octahedral sites. There are four symmetrically non-equivalent cation sites, with three of them occupied mainly by (Ta5+ + Nb5+) and one by Li+. The four distinct octahedra share edges, forming two types of zigzag chains (A and B) extending along the b axis. The A chains are built exclusively of (Ta,Nb)O6 octahedra (M1 and M2), whereas the B chains consist of alternating (Ta,Nb)O6 and LiO6 octahedra (M3 and M4, respectively). The average M1-O, M2-O, M3-O and M4-O bond lengths are 2.011, 2.004, 1.984, and 2.188 Å, respectively. Among the four octahedra, M3 is the least distorted and M4 the most. The refined Ta contents at the M1, M2 and M3 sites are 0.641 (2), 0.665 (2), and 0.874 (2), respectively, indicating a strong preference of Ta5+ for M3 in the B chain. The refined composition of the crystal investigated is Li0.96Mn0.03Na0.01Nb0.82Ta2.18O8.

_cell_length_a 7.4425(4) Å
_cell_length_b 5.0493(3) Å
_cell_length_c 15.2452(7) Å
_cell_angle_alpha 90.00°
_cell_angle_beta 107.381(3)°
_cell_angle_gamma 90.00°
_cell_volume 546.75(5) Å3
_cell_formula_units_Z 4
Sorry, only registered users may post in this forum.

Click here to login

Mineral and/or Locality is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization.
Copyright © and the Hudson Institute of Mineralogy 1993-2018, except where stated. relies on the contributions of thousands of members and supporters.
Privacy Policy - Terms & Conditions - Contact Us Current server date and time: January 16, 2018 19:23:53
Go to top of page