Am'oc0"ri889.arm'}      Manganous  Oxides  and  Carbonate.  523. 
the  mixture  remained  neutral,  and  the  manganous  chloride  formed 
was  equivalent  to  the  oxygen  which  entered  into  combination.  The 
further  action  of  chlorine  is  indirect,  hydrochloric  acid  and  not  man- 
ganous chloride  being  formed. 
Bromine  behaves  in  a  similar  manner,  but  the  reaction  is  slower. 
Native  manganous  carbonate  or  diallogite  is  very  stable  and  remains 
unaltered  after  contact  with  aerated  water  for  3  years.  Precipitated 
manganous  carbonate  which  has  become  crystalline  remains  in  contact 
with  aerated  water  at  the  ordinary  temperature  without  forming  any 
peroxide.  Even  at  100°  the  amount  of  peroxide  formed  is  very 
minute.  If  the  precipitated  carbonate  remains  in  contact  with  aerated 
water  for  10  years,  about  one-third  is  decomposed,  and  the  product 
has  the  composition  MnO,Mn02.  Two  specimens  containing  respec- 
tively 80  and  70  per  cent,  of  manganous  carbonate  were  exposed  to 
the  air  in  the  dry  state  for  8  years;  in  the  first  case  33  per  cent,  and 
in  the  second  14  per  cent,  of  manganous  carbonate  remained,  the  rest 
having  been  converted  into  the  oxide  MnO,Mn02. 
The  oxide  MnO,Mn02  can  be  obtained  by  the  direct  combination 
of  manganous  hydroxide  and  hydrated  peroxide,  and  undergoes  no 
change  if  exposed  to  air  for  5  months  in  the  dry  state  or  under  water. 
Manganous  carbonate,  when  exposed  to  the  air  at  the  ordinary  tem- 
perature, yields  no  oxide  higher  than  MnO,Mn02;  but  when  man- 
ganous carbonate  is  exposed  to  air  at  100°  for  250  hours  only  two- 
thirds  remains  unaltered,  the  rest  being  converted  into  an  oxide  which 
contains  considerably  more  oxygen  than  is  required  by  the  formula 
MnO,Mn02.  At  200°,  after  30  hours,  the  oxide  formed  contains 
92  per  cent,  of  manganese  peroxide.  The  oxide  MnO,Mn02  under- 
goes no  further  oxidation  at  100°. 
Chloralamid,  a  new  hypnotic,  was  introduced  by  v.  Mehring.  It 
is  a  product  of  chloral  anhydride  (CCl3CHO)  and  formamid  (CHONH^  and  has 
the  formula  CC13CH<^^^qjjq.  It  is  chloral-formamid,  and  forms  colorless  crys- 
tals, soluble  in  nine  parts  of  water  and  in  one  and  a  half  parts  of  alcohol.  Its 
taste  is  mild,  slightly  bitter,  but  not  biting.  The  watery  so^tion  keeps  well  ; 
but  when  heated  or  in  the  presence  of  alkali,  chloral  hydrate  and  ammonium 
formate  are  produced.  It  has  been  given  in  doses  of  2  to  3  grams  (30  to  45 
grains) ;  sleep  is  usually  produced  in  one-half  to  three-quarters  of  an  hour. 
No  unpleasant  after-symptoms  and  no  circulatory  disturbances  have  been 
observed. 
