在太空舱里，为了保持舱内O2 、CO2 气体含量的相对稳定，常用NiFe2O4作催化剂将宇航员呼出的CO2转化为O2 。9g,T6h4M,O.B7K7G8s2m0S
NiFe2O4中铁元素的化合价为+3价，则Ni的化合价为(Y'g.S8@8N5N5u2k9g,T6h4M,O.B7K7G8s2m0S
A．+19g,T6h4M,O.B7K7G8s2m0S
B．+29g,T6h4M,O.B7K7G8s2m0S
C．+39g,T6h4M,O.B7K7G8s2m0S
D．+49g,T6h4M,O.B7K7G8s2m0S