No abstract

No abstract

No abstract

C8H14Br2N2, monoclinic, I2/a (no. 15), a = 9.0331(9) Å, b = 13.4475(14) Å, c = 27.586(3) Å, β = 94.879(9)°, Z = 12, V = 3338.8(6) Å3, Rgt(F) = 0.0582, wRref = 0.0885, T = 290 K.

The original technique for a strong uniaxial elastic compression of moncrystals up to 5 à 6 kbar is described. It permits to avoid difficulties in mounting and frequent destruction of samples that are characteristic for conventional methods of uniaxial compression between two anvils. In the technique under consideration a sample in the form of rectangular parallelepiped is firmly fastened with the help of polymerized epoxy in an elastic steel ring along ''x'' direction, and afterward a tensile stress is to be applied to the ring in ''y'' direction. The ring transforms a tensile stress into the compressive one, applied to the both ends of the sample in the plane of the ring. Axial distribution of stress in the ring and a solid junction secure the sample of a premature destruction. Moreover, in the case if the plastic deformation of a monocrystal develops by a sliding process, the fixation of the main cleavage planes of the crystal inside the ring moves the plastic flow limit away until it starts developing along the not supported secondary cleavage planes. Advantages and possibilities of the technique are illustrated by some experimental results obtained in the system of Bi x Sb 1-x alloys and in p-GaAs/Al x Ga 1-x As heterostructures. m36.p13