164 
RESEARCHES  ON  HYPOPHOSPHITE  OF  LIME. 
water,  scarcely  soluble  in  ether  and  absolute  alcohol.  Soluble  in 
fixed  and  volatile  oils,  it  is  precipitated  when  they  become  rancid. 
It  crystallizes  with  difficulty;  the  crystals  contain  two  equivalents 
of  water  (PO,  CaO,  2  HO.)  Its  solution,  exposed  to  the  air,  is 
transformed  into  carbonate  and  biphosphate  of  lime.  Oxygen 
converts  it  first  into  phosphite  and  then  into  phosphate.  It  im- 
mediately decolorizes  a  solution  of  sesquisulphate  of  manganese 
(Mn2Os,3S03)._ 
Sulphur,  selenium,  and  tellurium,  also  decompose  it  into  phos- 
phite, then  into  phosphate,  with  formation  of  sulphide,  selenide, 
or  telluride  of  calcium. 
Boron,  silicon,  and  carbon  decompose  it  by  heat,  borate,  sili- 
cate, or  carbonate  of  lime  is  formed,  and  phosphorus  evolved  in 
vapor. 
Hydrogen  decomposes  it  into  phosphate  and  phosphuretted 
hydrogen. 
Hydrochloric,  hydriodic,  hydrobromic,  and  hydrofluoric  acids 
decompose  it  into  phosphate,  phosphuretted  hydrogen,  and  a 
haloid  salt. 
Nitric  acid  converts  it  into  phosphate,  hyponitric  acid  being 
evolved. 
The  alkaline  bases  decompose  it  into  phosphate  and  phosphide. 
The  alkaline  carbonates  when  boiling,  and  the  alkaline  sul- 
phates in  the  cold,  transform  it  into  an  alkaline  hypophosphite, 
and  carbonate  or  sulphate  of  lime. 
It  precipitates  metallic  gold  from  its  solutions. 
In  a  solution  of  nitrate  of  silver  it  produces  a  white  precipi- 
tate, which  rapidly  turns  brown  ;  if  the  hypophosphite  be  added 
in  excess  in  the  cold,  it  reduces  the  silver  to  the  metallic  state 
after  some  time ;  by  the  aid  of  heat  the  reduction  is  more  rapid. 
In  a  dilute  solution  of  bichloride  of  mercury  it  produces  a 
crystalline  precipitate  of  chloride.  If  added  in  excess,  it  reduces 
the  mercury  to  the  metallic  state. 
From  a  solution  of  sulphate  of  copper  it  precipitates  the  oxide, 
which  a  continued  ebullition  reduces  to  the  metallic  state. 
3*  Adulterations. 
Hypophosphite  of  lime  may  contain  phosphite,  phosphate,  or 
carbonate  of  lime. 
These  three  adulterations  are  separated  by  cold  distilled  water, 
in  which  they  are  insoluble. 
