@article{KutzschbachWunderKrstulovicetal.2016,
  author    = {Kutzschbach, Martin and Wunder, Bernd and Krstulovic, Marija and Ertl, Andreas and Trumbull, Robert B. and Rocholl, Alexander and Giester, Gerald},
  title     = {First high-pressure synthesis of rossmanitic tourmaline and evidence for the incorporation of Li at the X site},
  series = {Physics and chemistry of minerals / in cooperation with the International Mineralogical Association (IMA)},
  volume    = {44},
  journal   = {Physics and chemistry of minerals / in cooperation with the International Mineralogical Association (IMA)},
  publisher = {Springer},
  address   = {New York},
  issn      = {0342-1791},
  doi       = {10.1007/s00269-016-0863-0},
  pages     = {353 -- 363},
  year      = {2016},
  abstract  = {Lithium is an important component of some tourmalines, especially in chemically evolved granites and pegmatites. All attempts at synthesizing Li-rich tourmaline have so far been unsuccessful. Here we describe the first synthesis of rossmanitic tourmaline at 4 GPa and 700 degrees C in the system Li2OAl2O3SiO2B2O3H2O (LASBH) from seed-free solid starting materials consisting of a homogenous mixture of Li2O, gamma-Al2O3, quartz and H3BO3. The solid run products after 12-day run duration comprise rossmanitic tourmaline (68 wt\%), dumortierite (28 wt\%) and traces of spodumene (3 wt\%) and coesite (1 wt\%). Tourmaline forms idiomorphic, large prismatic crystals (30 X 100 mu m), which are inclusion free and chemically unzoned. The refined cell dimensions of the tourmaline are: a = 15.7396(9) angstrom, c = 7.0575(5) angstrom, V = 1514.1(2) angstrom 3. Conventionally, the Li+ ion is assumed to exclusively occupy the octahedral Y site in the tourmaline structure to a maximum of 2 Li per formula unit (pfu). However, the chemical composition of our synthetic tourmaline determined by electron microprobe and secondary ion mass spectroscopy results in the formula: (X)(square Li-0.67(11)(0.33(11)))(Y)(Al2.53(10)Li0.47(10))(Z)(Al-6)T(Si5.42(15)B0.58(15))O-18(B)(BO3)(3)(V+W)[(OH)(2.40(3))O-1.60(3)], wherein a significant amount of Li occupies the X site for charge balance requirements. Reliable assignment of the OH-stretching vibrations in a polarized single-crystal Raman spectrum such as a single-crystal XRD structure refinement, confirms the incorporation of Li at the X site [0.24(9) and 0.15(5) Li-X pfu, respectively]. The SREF data show that the LiO1 distances are shortened significantly in order to compensate for the smaller ionic radius of Li+ compared to Na+, K+ or Ca2+ at the X site, i.e., Li is closer to the Si6O18 ring and to a sevenfold coordination with oxygen.},
  language  = {en}
}
@article{KutzschbachWunderWannhoffetal.2021,
  author    = {Kutzschbach, Martin and Wunder, Bernd and Wannhoff, Iris and Wilke, Franziska Daniela Helena and Couffignal, Fr{\´e}d{\´e}ric and Rocholl, Alexander},
  title     = {Raman spectroscopic quantification of tetrahedral boron in synthetic aluminum-rich tourmaline},
  series = {American mineralogist : an international journal of earth and planetary materials},
  volume    = {106},
  journal   = {American mineralogist : an international journal of earth and planetary materials},
  number    = {6},
  publisher = {Mineralogical Society of America},
  address   = {Washington, DC [u.a.]},
  issn      = {0003-004X},
  doi       = {10.2138/am-2021-7758},
  pages     = {872 -- 882},
  year      = {2021},
  abstract  = {The Raman spectra of five B-[4]-bearing tourmalines of different composition synthesized at 700 degrees C/4.0 GPa (including first-time synthesis of Na-Li-B-[4]-tourmaline, Ca-Li-B-[4]-tourmaline, and Ca-bearing square-B-[4]-tourmaline) reveal a strong correlation between the tetrahedral boron content and the summed relative intensity of all OH-stretching bands between 3300-3430 cm(-1). The band shift to low wavenumbers is explained by strong O3-H center dot center dot center dot O5 hydrogen bridge bonding. Applying the regression equation to natural B-[4]-bearing tourmaline from the Koralpe (Austria) reproduces the EMPA-derived value perfectly [EMPA: 0.67(12) B-[4] pfu vs. Raman: 0.66(13) B-[4] pfu]. This demonstrates that Raman spectroscopy provides a fast and easy-to-use tool for the quantification of tetrahedral boron in tourmaline. The knowledge of the amount of tetrahedral boron in tourmaline has important implications for the better understanding and modeling of B-isotope fractionation between tourmaline and fluid/melt, widely used as a tracer of mass transfer processes.},
  language  = {en}
}