This  compound,  wliicli  may  be  regarded  as  formed  by  the  union
of  the  radicals  phenyle  and  benzoyle,  is  obtained,  along  with  other
products,  when  benzoate  of  lime  is  distilled  with  a  little  lime.  A
red  liquid  passes  over,  which  is  rectified.  These  then  distil,  first
benzole  or  hyduret  of  phenyle,  mixed  with  other  bodies ;  then,
the  temperature  rapidly  rises  till  it  reaches  600°  F.,  the  receiver
is  changed,  and  the  liquid,  which  distils  between  600°  and  620°,
is  collected  apart.  It  is  nearly  pure  benzophenone,  and  on  stand-
ing concretes  into  a  mass  of  crystals.  It  is  purified  by  recrystal-
lisation  in  a  mixture  of  alcohol  and  ether.  It  forms  very  fine
large  transparent  crystals,  which  are  rhombic  prisms.  It  melts
at  115°  F.,  and  boils  at  600°;  is  insoluble  in  water,  soluble  in
alcohol,  and  still  more  in  ether.
Its  formation  from  benzoate  of  lime  is  thus  explained,  2  (Ca  0,
Ci*  H5  Os)  =  2  (Ca  0,  C  0»)  +  Cae  Hio  Oa.
The  presence  of  benzole  is  due  to  a  secondary  decomposition,  for
benzoic  acid,  with  excess  of  lime,  yields  benzole;  and  benzo-
phenone, with  caustic  alkalies,  also  yields  benzole  and  benzoate.
But  along  with  the  benzophenone  are  found  two  carbohydrogens,
which  are  isomeric  or  polymeric  with  naphthaline.  These  are
both  crystalline,  fusible  and  volatile,  but  differ  in  their  solubility
in  alcohol  and  ether.  Naphthaline  is  €20  Hs ,  and  if  we  suppose
these  bodies  to  be,  one  €20  Hs ,  isomeric  with  naphthaline,  and
the  other  Cso  Hi2,  polymeric  with  naphthaline,  we  can  understand
their  formation  from  benzophenone.  For  2  (€26  Hio  Oz )  =  2  C  On
+  Cao  Hs  +  Cso  Hi2.
