Pyrolusite crystal structure

Most Mn(in, IV) minerals have crystal structures that fall into one of three major groups Chain, tunnel, and layer structures (22-24). The chain structures consist of cross-linked single or double rows of MnO octahedra running parallel to the c axis (e.g., pyrolusite). The tunneled structures are formed from two or more cross-linked... 

Figure 1. Polyhedral representations of crystal structures of Mn oxide minerals with chain or tunnel structures. (A) Pyrolusite. (B) Ramsdellite.

The crystal structure of pyrolusite, or f -Mn02, is the simplest one within the family of compounds with tunnel structures. The manganese atoms occupy half of the octahedral voids in the hexagonal close packing of oxygen atoms in an ordered manner, thus forming a rutile-type structure. The distorted MnOg units build... 

Therefore De WoUf proposed in his model that the crystal structure of y-Mn02 intergrowth of pyrolusite and ramsdeUite domains. An ideaUzed section of the y-Mn02 intergrowth structure is shown in Figure 3.1c together with the parent... 

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