Synchysite

Synchysite is a group of carbonate minerals.^[3] The three isostructural chemical end members are synchysite-(Ce), synchysite-(Nd) and synchysite-(Y). Huanghoite-(Ce) belongs to the group, but has a different symmetry and calcium is replaced by barium.^[4][5]

Synchesite group

Mineral name	Chemical formula	Symmetry	Space group
Huanghoite-(Ce)	BaCe(CO 3) 2F	${\displaystyle 3\;2/m}$	${\displaystyle R\;{\overline {3}}\;m}$
Synchysite-(Ce)	Ca(Ce,La)(CO 3) 2F	${\displaystyle 2/m}$	${\displaystyle C\;2/c}$
Synchysite-(Nd)	CaNd(CO 3) 2F	${\displaystyle 2/m}$	${\displaystyle C\;2/c}$
Synchysite-(Y)	CaY(CO 3) 2F	${\displaystyle 2/m}$	${\displaystyle C\;2/c}$

Synchysite
A synchysite with unknown end-member composition
General
Category	Minerals
Formula	Ca(REE)(CO3)2F
Strunz classification	5.BD.
Crystal system	Monoclinic and trigonal
Space group	C2/c (monoclinic)
Identification
Mohs scale hardness	4.5
References	[1][2]