METHODS
CaCl
2 and Na2C2O4 solutions
All preparations and experiments were conducted at
room temperature (25 °C), and all chemicals were
analytical grade. CaCl2 · 2 H2O (ASP Ajax Finechem)
and Na
2C2O4 (ASP Ajax Finechem) were from the
same 1 M stock solutions in distilled (dI) water. CaOx
crystals were produced by using the required concentrations of CaCl
2 (1 mM or 4 mM) and Na2C2O4
(1 mM or 4 mM) diluted from the stock solutions with
dI water. From the previous study 11 , the appropriate
value of [Ca 2+]/[C2O42 – ] is 1 because surface characteristics cannot be classified when values of 2 or 3 are
used.