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In Hermann–Mauguin notation, space groups are named by a symbol combining the point group identifier with the uppercase letters describing the lattice type. Translations within the lattice in the form of screw axes and glide planes are also noted, giving a complete crystallographic space group. These are the Bravais lattices in three dimensions:
A space group is called symmorphic (or split) if there is a point such that all symmetries are the product of a symmetry fixing this point and a translation. Equivalently, a space group is symmorphic if it is a semidirect product of its point group with its translation subgroup. There are 73 symmorphic space groups, with exactly one in each ...
This category lists minerals that display the Pbam (No. 55) space group symmetry of the orthorhombic crystal system. Pages in category "Minerals in space group 55" The following 5 pages are in this category, out of 5 total.
Bonaccordite has an orthorhombic crystal system with a point group of 2/m 2/m 2/m. The crystals are structured as elongated prisms within another material. [4] There has been no observed cleavages or twinning. Space group has been determined as [Pbam] and cell dimensions were calculated to a = 9.213(6) b = 12.229(7) c = 3.001(2) Z = 4. [4]
In mathematics, a layer group is a three-dimensional extension of a wallpaper group, with reflections in the third dimension. It is a space group with a two-dimensional lattice, meaning that it is symmetric over repeats in the two lattice directions.
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Lead(II,IV) oxide is lead(II) orthoplumbate(IV) [Pb 2+] 2 [PbO 4− 4]. [3] It has a tetragonal crystal structure at room temperature, which then transforms to an orthorhombic (Pearson symbol oP28, Space group Pbam, No. 55) form at temperature 170 K (−103 °C).
The symbol of a space group is defined by combining the uppercase letter describing the lattice type with symbols specifying the symmetry elements. The symmetry elements are ordered the same way as in the symbol of corresponding point group (the group that is obtained if one removes all translational components from the space group).