Lanthanum decahydride

22 December 2017 - Chemical Zoo

lanthanumdecahydride.PNGIn last week's Angewandte Geballe et al. (Carnegie) report on a new strategy towards the elusive metallic hydrogen DOI. In a previous edition of this blog we were left with Dias and Silvera of Harvard trying to find out where their sample went, so a bit of good news is in order.

Instead of filling up a diamond anvil cell with just hydrogen Geballe looked at a combination of hydrogen and lanthanum. At 1000 K and 170 GPa interesting things happened consistent with the formation of LaH10. In the experimentally determined crystal structure the La atoms form a cubic fcc lattice and each La atom sits in a 32-hydrogen atom 18-sided cage. The hydrogen atoms are separated by 1.1 A, a distance predicted for solid metallic hydrogen. Direct observation of a metallic sheen was not reported.