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The structure of SbSBr which was reported in approximate form by D6nges (1950) has been refined by means of Fourier syntheses on (001). There are four units of SbSBr in the unit cell for which a = 8.26, b = 9.79 and c = 3.97 A. The space group is Pnam and the atoms all lie in the mirror planes at z = ¼ and z = ~. The refinement resulted in shifts of as much as 0.4 i in the bond distances and suggested a somewhat different interpretation of the bonding than that given by D6nges. The new interpretation is a structure consisting of pleated chains of Sb and S atoms along the c axis with bromine present as Br-outside the chains. Each Sb has one S atom at 2-49 l and two S atoms at 2.67 A. Each S atom is similarly bonded to three Sb atoms. The bond angles around Sb are 84.1 ° (2) and 96.3 ° (1) while those around S are 95.9 ° (2) and 96.3 ° (1). The nearest neighbors of Br-are two Sb at 2.94/~ and one S at 3.46 A. THE CRYSTAL STRUCTURE OF ANTIMONY (III) SULFOBROMIDETable 4. Comparison of observed and calculaled structure factors for SbSBr .I % % ,. k J. ~,o % ,. '. ~, 1 % ~, ~ ~ J % eo

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In the study of X-ray absorption fine structure, one is faced with the task of measuring sample absorbance over an extended wavelength region. For the sake of accuracy, these measurements are often carried out on a fixed-count basis. Manual collection of the data at a hundred or more spectrometer settings is a tedious and time-consuming chore. This paper describes an automated system for accumulating absorption data.The equipment is used in conjunction with a Philips wide-range goniometer employed as a single-crystal spectrometer. It consists of: (1) a four-position sample changer, (2) a fixed-count selector for each sample position, (3) a five-digit counter and paper tape printer which register and record sample identification and counting times based on a 60-cps clock frequency, and (4) a programmer. The spectrometer advance is accomplished using the Philips step-scan arrangement. An IBM 7094 FORTRAN program for data reduction and computation will be described. The possibility of using X-ray absorption fine-structure measurements as a quantitative method for determining the various absorbing species will be discussed.