Or FLS--a Fortran Crystallographic Least-Squares Program

Abstract

The structure of Na2[Zr(SO4)3].3H20 has been determined'~y single-crystal X-ray analysis and refined by least-squares. The crystals, which are orthorhombic with space group P21212t, have the unit-ceU dimensions a=22.16, b=7.73, c=7.08 /~. The structure consists of spirals of composition [Zr(SO4)a(H20)2], extending in the [001] direction which are held together by the sodium atoms and a single lattice water molecule. Two of the sulphate groups form bridges between the zirconium atoms while two more sulphate groups are each doubly bonded to each zirconium atom. All sulphate groups have two terminal oxygen atoms. There are two water molecules coordinated to each zirconium atom. The hydrogen atoms of these water molecules bridge to oxygen atoms of sulphate groups and probably give rigidity to the spiral structure.

Neutron diffraction at 15 K and ab initio molecular-orbital studies of the structure of N,N'-diformohydrazide

“…The lattice parameters in Table 1 there were four recorded with net negative intensities which were not significantly different from zero. The initial atomic coordinates used were those of Hope & Ottersen (1978) with assumed isotropic temperature factors of 0.006A 2 for non-hydrogen atoms and 0.009 A 2 for H. The refinement was by full-matrix least squares (Busing, Martin & Levy, 1962). The quantity minimized was w(F 2 _ Fc),22 where w -t = [02 + (0.01F2) 2 + (2850/F2o)2] ~/2.…”

Neutron diffraction at 16 K and ab initio molecular-orbital studies of the structure of formamide oxime

“…Full-matrix least-squares refinement was carried out with a modified version of the computer program by Busing, Martin & Levy (1962). The quantity minimized was ~ wd 2, where w = 1/a2(F2), with a(F 2) = [a¢ou,te r2…”

The crystal structure of the dimeric complex (C8H11PdCl)2

“…The scattering factors were taken from International Tables for X-ray Crystallography (1962) A full-matrix least-squares calculation with the local version SIRIUS of the program ORFLS (Busing, Martin & Levy, 1962) was used to refine the atomic coordinates and isotropic temperature factors of all non-hydrogen atoms. R fell to 0.10 and was then reduced to 0.051 by anisotropic refinement.…”