30 



considered, and here too relation of phases has been neglected 

 (diminishing factor as nndei- 3). ^"1 



The influence of the heat motion, of wliich nothing is known 

 for the different electrons, was left out of cons-ideration. The radius 

 of the comparative!}' small inner ring of Li has always been taken 

 equal to Bohr's initial value'); in all the suppositions mentioned 

 if has been examined what values of rhe radii of the other orbits 

 made the calculated and observed intensity concordant. Finally the 

 supposition "rings, on— = ± 5/6 times the radius of a two-quanta 

 ring in a free H"-ion" appeared to give the best agreement. As a 

 specimen some of the calculated intensities are given i. a. those for 

 Bohr's initial values of q, and in the last column the case 

 jjH — = dz 0,6a and (ju-\-= =*= 0,05<2, which is in agreement with 

 the observations. 



In how far the factors neglected here, as heat motion, and the 

 occurrence of non circular orbits, may affect the conclusions drawn 

 here, must at present be left undecided. 



4. Summary. The Röntgenogram of lithium hydride (method 

 Dëbye-Scherrer) has been taken with Kcr rays. LiH appears to 

 crystallize regularly with 4 LiH per elementary cell. [Side a = 

 4.10.10-8 cm.]. The density is found to be 0.76 ± 0,01. On the 

 basis taken for the calculation the following assumptions appeared 

 to be most satisfactory : NaCl-structure with positive Li-ions and 

 negative H-ions; systems of two-electron rings both round Li- and 

 H-nuclei with radii resp. rt 0,05a and ±0,6^, the planes of which 

 are normal to non-intersecting trigonal axes. 



In conclusion we express oui- great indebtedness to Prof. Smits 

 for his valuable help and the great interest he took in our work. 



Laboratory of Physical and Inorganic Chemistry. 

 Amsterdam, February 15, 1922. 



1) In Coster's computation of the binding circles of diamond this has also been 

 introduced, whereas Kolkmeyer bases his calculations on an undisturbed phase 

 relation. 



s) Bohr, Phil. Mag. (VI) 26 490 (1913). 



