An augelite, Al2(PO4) (OH)3, from Mono County, California, has unit cell a = 13.124 ± 0.006, b = 7.988 ± 0.005, c = 5.066 ± 0.003 Å, β = 112.25 ± 0.02° and its space group is C2/m, in agreement with Peacock and Moddle (1941).
Patterson maps were calculated from three-dimensional Intensities and solved by the minimum function method. The structure was refined by a sequence of Fourier syntheses and least-squares techniques to an R value of 6.6 percent for all and 5.0 percent for all but the eight strongest reflections.
Al has two different coordinations in this structure. One is coordinated to four OH and two O and the other to three OH and two O. The P atom is coordinated to four O. Four A1 polyhedra, two of each type, are linked together by sharing OH-OH edges. These groups in turn are connected to P-tetrahedra sharing corner O atoms.