Premium
CaO‐As 2 O 5 ‐H 2 O System at 23°± 1°C
Author(s) -
Bothe James V.,
Brown Paul W.
Publication year - 2002
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.2002.tb00069.x
Subject(s) - chemistry , solubility , apatite , hydrate , phase diagram , calcium , ternary numeral system , nuclear chemistry , crystallography , phase (matter) , mineralogy , organic chemistry
The phase diagram for the ternary system CaO‐As 2 O 5 ‐H 2 O at 23°± 1°C is plotted. The calcium arsenates represented are Ca(H 2 AsO 4 ) 2 , CaHAsO 4 ·H 2 O, Ca 5 H 2 (AsO 4 ) 4 ·9H 2 O, Ca 3 (AsO 4 ) 2 · x H 2 O ( x = 3⅔ and 4¼), Ca 5 (AsO 4 ) 3 OH (apatite), and Ca 4 (OH) 2 (AsO 4 ) 2 ·4H 2 O. The solubility data indicate the following invariant points: Ca(H 2 AsO 4 ) 2 –CaHAsO 4 ·H 2 O–solution, CaHAsO 4 ·H 2 O–Ca 5 H 2 (AsO 4 ) 4 ·9H 2 O–solution, Ca 5 H 2 (AsO 4 ) 4 ·9H 2 O–Ca 3 (AsO 4 ) 2 ·4¼H 2 O–solution, Ca 3 (AsO 4 ) 2 ·3⅔H 2 O–Ca 4 (OH) 2 (AsO 4 ) 2 ·4H 2 O–solution, and Ca 4 (OH) 2 (AsO 4 ) 2 ·4H 2 O–Ca(OH) 2 –solution. The tricalcium arsenate Ca 3 (AsO 4 ) 2 ·3⅔H 2 O is shown to be the only hydrate to dissolve congruently.