Refinement of the Crystal Structure of Vlasovite from Burpala Massif (Russia)

The structural model and chemical composition of vlasovite from the Burpala massif (Russia) have been determined using X-ray diffraction methods and electron probe microanalysis. The crystal structure has been refined in the sp. gr. Cc to R = 1.4% (Rw = 1.8%) with the following unit-cell parameters: a = 11.0396(3) A, b = 10.1042(2) A, c = 8.5696(2) A, β = 100.307(1)°, V = 940.48(4) A3, and Z = 4.