SINGLE-CRYSTAL X-RAY STRUCTURE DETERMINATIONS ON CALCIUM AND STRONTIUM DEUTERIDE, CAD2 AND SRD2

Pieces of calcium and strontium metal react under definite conditions with deuterium in a stainless steel tube to yield crystals of CaD2 and SrD2. These have the shape of colourless or white octahedra. The alka line earth metals react at 1000 degrees C under p(D-2) = 1 bar. Single crystals of CaD2 and SrD2 are found - after the reaction is carried o ut - on the surface of the large pieces of these deuterides. Crystals sufficient in size for X-ray structure determinations were selected: C aD2 - Space group Pnma, Z = 4, a = 5.995(1) Angstrom b = 3.598(1) Angs trom, c = 6.806(4) Angstrom, R/R(w) = 0.039/0.045 with N(F-0(2)) great er than or equal to 3 sigma(F-0(2)) = 126, N(var.) = 11, SrD2 - Space group Pnma, Z = 4, a = 6.361(2) Angstrom b = 3.857(2) Angstrom c = 7.3 03(4) Angstrom, R/R(w) = 0.020/0.023 with N(F-0(2)) greater than or eq ual to 3 sigma(F-0(2)) = 451, N(var.) = 12. CaD2 and SrD2 are isotypic with BaD2 [1], EuD2 [2] und YbD2 [3]. Their structures differ in mino r details from the PbCl2 structure type.