Application of normal probability plot analysis to lutetium orthoborate factors and parameters

The methods of normal probability plot analysis have been applied to two nearly complete sets of structure factors ( F meas ) and the corresponding objectively assigned standard deviations (σ F meas ) obtained by diffractometer measurement with two different crystals of lutetium orthoborate. The least‐squares derived positional and thermal vibration parameters are shown to be too small by a factor of 1.8, and the σ F meas to be overestimated by a factor of 1.55. The two sets of F meas are found to contain a small but parallel bias. The lattice constants of rhombohedral calcite‐type LuBO 3 are measured as a H = 4.91538±0.00002 Å and c H = 16.21200±0.00003 Å at 298°K, with six formulas in the unit cell, space group R c . The Lu–O distance in this six‐coordinated Lu compound is 2.240±0.002 Å (corrected standard deviation). The B–O distance in the BO 3 triangular groups is 1.370±0.005 Å. The characteristic Θ temperature is estimated as 446±19°K.