^"^'B^l'ms^'"'^'}'       Action  of  Alkaline  'Phosphates.  617 
ACTION  OF  ALKALINE  PHOSPHATES  ON  THE  ALKA- 
LINE EARTHS  AND  OTHER  OXIDES.^ 
By  L.  Ouvraed. 
The  oxide  or  a  salt  of  the  alkaline  earth  was  dissolved  in  the  fused 
phosphate,  with  or  without  an  alkaline  chloride,  allowed  to  cool  slowly, 
and  the  product  treated  with  water. 
Barium  oxide  dissolves  readily  in  potassium  metaphosphate  or  pyro- 
phosphate, and  in  both  cases  yields  the  pyrophosphate  Ba2P207  in  mo- 
noclinic  prisms  which  dissolve  readily  in  dilute  acids  and  in  concen- 
trated sulphuric  acid.  In  presence  of  potassium  chloride,  the  result  is 
the  same  if  the  proportion  of  the  phosphate  is  not  below  5  per  cent., 
but  with  a  lower  proportion  a  chlorophosphate  is  formed.  Precipi- 
tated barium  phosphate  behaves  io  the  same  manner  as  the  oxide. 
Barium  sulphate  also  dissolves  and  yields  the  pyrophosphate,  the 
excess  of  sulphate  crystallizing  in  the  form  of  barytes. 
Potassium  orthophosphate  with  barium  oxide,  chloride,  or  phosphate, 
yields  the  compound  P205,2Ba0,K20  in  transparent,  dendritic  crystals, 
soluble  in  dilute  acids. 
Sodium  metaphosphate  and  pyrophosphate  yield  either  barium 
pyrophosphate  or,  if  the  proportion  of  barium  is  considerable,  the  com- 
pound P205,3BaO,  which  crystallizes  in  large,  transparent,  lamellse, 
seemingly  belonging  to  the  regular  system;  sp.  gr.  4*1  at  16°.  The 
crystals  dissolve  in  dilute  acids  and  in  concentrated  sulphuric  acid. 
Sodium  chloride  promotes  crystallization,  but  if  the  proportion  exceeds 
a  certain  limit,  a  chlorophosphate  is  formed.  Sodium  orthophosphate 
yields  only  the  compound  PgOgjSBaO.  Barium  sulphate  is  not  decom- 
posed by  the  sodium  phosphates  ;  it  dissolves  to  a  certain  extent  but 
crystallizes  unaltered  on  cooling. 
Calcium  oxide,  phosphate,  or  sulphate  with  potassium  metaphos- 
phate or  pyrophosphate,  yield  the  compound  P205,CaO,K20  in  large, 
transparent  hexagonal  lamellae  derived  from  the  regular  octahedron ; 
sp.  gr.  2*7.  The  same  compound  is  also  obtained  from  calcium  chloride 
or  fluoride  if  the  alkaline  phosphate  is  in  sufficient  excess ;  it  dissolves 
readily  in  dilute  acids.  Tripotassium  phosphate  and  calcium  oxide 
form  the  compound  P205,2CaO,K20,  which  has  the  same  crystalline 
form  as  the  corresponding  barium  salt,  and  has  already  been  described 
by  Grandeau,  who  obtained  it  by  Debray's  method.    Sodium  meta- 
1  Compt.  Rend.,  cvl,  1599  and  1729;  reprinted  from  Jour.  Chem.  Soc,  October, 
p.  1033, 1035. 
