metameric
位变异构的
位变异构的
metameric adj 1 :
having the body divided into successive metameres or segments ,
as in earthworms or lobsters [
synonym : {
metameric },
{
segmental }, {
segmented }]
isomeric \
i `
so *
mer "
ic \ ([
imac ]`
s [-
o ]*
m [
e ^]
r "[
i ^]
k ),
a . [
Iso -
Gr .
me `
ros part :
cf .
F .
isom ['
e ]
rique .] (
Chem .)
Having the same chemical composition and molecular weight ;
having the same number of atoms of each kind in the molecule ;
--
said of chemical compounds with known chemical composition .
This property used to be called {
metameric }
to distinguish it from other forms of isomerism .
[
PJC ]
Note :
Formerly the term isomeric applied also to comopounds having the same percentage chemical composition ,
even if the number of atoms in a molecule differed .
In the 1913 dictionary isomeric was defined as :
"
Having the same percentage composition ; --
said of two or more different substances which contain the same ingredients in the same proportions by weight ,
often used with with .
Specif .:
(
a )
Polymeric ;
i .
e .,
having the same elements united in the same proportion by weight ,
but with different molecular weights ;
as ,
acetylene and benzine are isomeric (
polymeric )
with each other in this sense .
See {
Polymeric }.
(
b )
Metameric ;
i .
e .,
having the same elements united in the same proportions by weight ,
and with the same molecular weight ,
but with a different structure or arrangement of the ultimate parts ;
as ,
ethyl alcohol and methyl ether are isomeric (
metameric )
with each other in this sense .
See {
Metameric }."
[
1913 Webster ]
Metameric \
Met `
a *
mer "
ic \,
a . [
Pref .
meta -
Gr . ?
part .]
1 . (
Chem .)
Having the same molecular formula ,
but possessing a different bonding structure and different properties ;
as ,
methyl ether and ethyl alcohol are metameric compounds .
See {
Isomeric }.
[
1913 Webster ]
Note :
The existence of metameric compounds is due to different arrangements of the same atoms in the molecule .
[
1913 Webster ]
2 . (
Biol .)
Of or pertaining to a metamere or its formation ;
as ,
metameric segmentation .
[
1913 Webster ]
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