Am.  Jour.  Pharm. ) 
December,  1898.  j 
Medicinal  LitJmnn  Carbonate. 
605 
One  gramme  of  pure  lithium  carbonate  requires  27-0745  c.c. 
of  normal  acid  for  complete  neutralization.  The  U.S. P.  requires  not 
less  than  26-8  c.c.  per  gramme,  corresponding  to  98-98  per  cent,  of 
pure  salt.  According  to  the  results  in  the  preceding  table  the 
average  of  thirteen  determinations  of  eight  samples,  eight  volumetric 
and  five  gravimetric,  is  98-4  per  cent.  Volumetric  alone,  98-41  per 
cent.  Eliminating  the  lowest  volumetric  result,  we  obtain  98-71 
per  cent,  as  the  average  of  seven  determinations  of  as  many  samples. 
In  the  Digest  of  Criticisms  on  the  U.S.P.  of  1890  (1897),  Part  \ 
p.  103,  we  find  the  following:  "One  gramme  carbonate  of  lithium 
requires  for  neutralization  27-745  c.c.  normal  sulphuric  acid;  Ph. 
Germ.  Ill  directs  at  least  26-8  c.c.  acid  for  one  gramme  of  the  salt, 
corresponding  to  96  59  per  cent,  of  the  pure  carbonate,  which  is 
exactly  the  strength  Curtman  has  found  in  all  the  specimens  exam- 
ined by  him." 
These  figures  are  correctly  quoted  from  Circ.  No.  112,  p.  676. 
There  are,  however,  several  errors  in  the  circular.  The  number 
of  cubic  centimeters,  27-745,  should  read  27-0745,  the  cipher  having 
been  inadvertently  omitted.  26-8  c.c.  of  normal  sulphuric  acid  do 
^/correspond  to  96-59  per  cent,  of  pure  carbonate,  but  to  98-98 
per  cent.,  which  is  probably  what  was  meant  and  is  correct  in  the 
U.S.P. 
98-98  per  cent,  is  a  trifle  higher  than  the  best  average  result 
obtained  by  the  writer,  viz.:  9871  per  cent.  The  writer  is  of  the 
opinion  that  the  mechanical  impurities  contribute  largely  towards 
lowering  the  per  cent. 
The  volumetric  and  the  gravimetric  methods  were  carefully  com- 
pared. The  conclusion  is  decidedly  in  favor  of  the  volumetric  process. 
According  to  the  above  data,  Lithium  Carbonate  is  a  light, 
white  powder,  with  occasional  crystalline  grains,  odorless  and  having 
an  alkaline  taste ;  permanent  in  the  air. 
Soluble  in  not  less  than  75  parts,  and  should  not  require  more 
than  80  parts  of  water  at  150  C,  and  in  140  parts  ol  boiling  water; 
much  more  soluble  in  water  impregnated  with  carbon  dioxide  ; 
insoluble  in  alcohol.  Soluble  in  dilute  nitric,  sulphuric,  hydrochloric 
and  acetic  acids;  with  active  effervescence. 
Fuses  at  a  low  red  heat ;  loses  carbon  dioxide  at  a  higher  tempera- 
ture, and  is  partially  converted  into  the  oxide.  It  imparts  a  crimson 
color  to  a  non-luminous  flame. 
