^""Dec'im""^"}        Action  of  Alkaline  Phosphates, 
619 
perature,  the  metaphosphate  yields  dendritic  crystals  of  the  compound 
P205,MgOj2Na20,  and  the  same  product  is  obtained  with  the  pyro- 
phosphate. It  is  readily  soluble  in  dilute  acids.  Sodium  orthophos- 
phate  yields  the  salt  2P205,3MgO,3Na20  in  dendritic  crystals  which 
depolarize  light. 
Zinc  and  cadmium  yield  compounds  which  are  strictly  analogous. 
"With  potassium  metaphosphate,  the  salt  P205,MO,K20  is  obtained  in 
highly  macled  crystals  which  depolarize  light  and  are  soluble  in  dilute 
acids.  Potassium  pyro-  or  ortho-phosphate  yields  monoclinic  prisms 
of  the  salt  P205,2MO,K20,  very  soluble  in  dilute  acids.  Zinc  and 
cadmium  phosphates  yield  the  same  products  as  the  oxides,  and  alka- 
line chlorides  have  no  effect  on  the  result  even  when  present  in  large 
excess.  The  compound  just  described  can,  in  fact,  be  obtained  by  the 
action  of  cadmium  or  zinc  phosphate  on  potassium  chloride. 
Sodium  metaphosphate  yields  the  salt  P205,MO,Na20,  described  by 
Wallroth,  or  the  salt  P265,2MO,Na20,  described  by  Scheffer,  or  a 
third  salt  P205,MO,2Na20 ;  according  to  the  relative  proportions  of 
the  oxides ;  sodium  pyro-  or  ortho-phosphate  yields  the  compounds 
P205,MO,2Na,0  and  Po05,2MO,]S"a20. 
Manganese  yields  products  similar  to  those  obtained  with  zinc  and 
cadmium,  but  in  presence  of  an  alkaline  chloride  chlorophosphates  are 
formed  if  the  proportion  of  alkaline  phosphate  falls  below  a  certain 
limit.  P205,MnO,K20  and  P205,2MnO,K20  crystallize  in  monoclinic 
prisms ;  P205,MnO,Na20  forms  highly  macled  rose-colored  prisms 
which  are  probably  triclinic.  P205,MnO,2Na20  and  P205,2MnO,Na20 
are  isomorphous  with  the  corresponding  zinc  and  cadmium  salts. 
Cobalt  and  nickel  form  strictly  analogous  compounds.  Potassium 
metaphosphate  yields  monoclinic  prisms  of  the  composition,  2P2O5, 
3MO,3K20,  and  the  pyro-  and  ortho-phosphate  yield  rhombic  crystals 
of  the  salt  P205,2MO,K20,  all  soluble  in  dilute  acids.  The  presence 
of  potassium  chloride  promotes  crystallization,  but  exerts  no  other  in- 
fluence on  the  result. 
Sodium  metaphosphate  yields  the  salt  9P2O5,10MO,8Na2O  in  macled, 
dichroic  violet  or  rose-colored  prisms,  or,  if  the  oxide  is  in  excess,  the 
salt  P205,2M03,]Sra20,  which  is  isomorphous  with  the  corresponding 
zinc  salt ;  sodium  pyro-  or  ortho-phosphate  yields  products  strictly 
analogous  to  those  obtained  with  zinc,  cadmium,  and  manganese.  In 
presence  of  sodium  chloride,  all  the  double  phosphates  of  nickel  or 
cobalt  are  converted  into  the  salt  P205,2MO,Na20. 
