research papers
The crystal structure of the new mineral takéuchiite, Me3BO5 (Me = Mg, Mn2+, Mn3+, Fe3+, Ti4+), has been derived by matching experimentally obtained high-resolution transmission electron microscope images with computed ones. The crystals are orthorhombic Pnnm or Pnn2, with a= 27.50 (1), b = 12.614 (2) and c = 6.046 (1) Å and Z = 24. The structure can be described as a periodic chemical twinning of the parent structure of pinakiolite, and is thus closely related to the other known chemical twins of pinakiolite, viz ludwigite and orthopinakiolite.