A dioctahedral phyllosilicate where the vacancy is ordered and occurs in the octahedral site where the OH,F anions reside on adjacent corners of the octahedron (i.e., cis orientation). Alternatively, the description of the cis site is off the mirror plane (based on the idealized layer symmetry, not necessarily the structure in its entirety) of the layer.
Cf., transvacant
See d value
As defined in the Bragg equation for diffraction, nλ = 2d Sinθ, where n is an integer, λ is the wavelength, θ is the glancing angle of incidence, and d is the (perpendicular) spacing between the diffracting planes. Because d is defined as a spacing, the term d spacing is redundant.
See Bragg equation
See point defect.
A trans-vacant phyllosilicate is dioctahedral with the vacancy ordered to the site where the OH,F anions are on opposite octahedral corners (i.e., trans orientation). Trans sites are located on the mirror plane of an ideal layer in a phyllosilicate.
Cf., cis-vacant
See layer.