A ternary alloy with PbCl2-type structure: TiNiSi(E)

Beck and coworkers have found E phases in several ternary systems of transition elements with either silicon or germanium at the composition 1:1:1. The crystal structure of TiNiSi(E) has been determined and refined by least squares with (limited) three-dimensional single-crystal data to a final R value of 0.086 (excluding 002 due to apparent extinction, and all nonobserved reflexions). The lattice parameters for the primitive orthorhombic cell are: a sub 0 = 6.1484=0.0012, b sub 0 = 7.0173=0.0014, c sub 0 = 3.6698=0.0007 A. The E phase is isotypic with PbCl2(C23), space group Pnam. All near-neighbor distances are within 0.06 A of the following average values: Ti-Ti 3.18, Ti-Ni 2.83, Ti-Si 2.61, Ni-Ni 2.67, Ni-Si 2.33 A. The numbers of nearneighbors are compared with those in Co2Si, theta Ni2Si and U3Si2. (Author)