Synchysite

Synchysite
A synchysite with unknown end-member composition
General
Category	Mineral
Formula (repeating unit)	Ca(REE)(CO3)2F
Strunz classification	5.BD.
Crystal system	Monoclinic and trigonal
Identification
Mohs scale hardness	4.5
References	[1]

Synchysite is a group of carbonate minerals.^[2] 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.^[3][4]

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	$2/m$	${\displaystyle C\;2/c}$
Synchysite-(Nd)	CaNd(CO 3) 2F	$2/m$	${\displaystyle C\;2/c}$
Synchysite-(Y)	CaY(CO 3) 2F	$2/m$	${\displaystyle C\;2/c}$

References

1. "Synchysite-(Ce)" (PDF). handbookofmineralogy. Retrieved 24 February 2013.
2. "Synchysite Group". Retrieved 24 February 2013.
3. "Synchysite-(Ce)". Retrieved 24 February 2013.
4. "Huanghoite-(Ce)". Retrieved 24 February 2013.