Journal of the Mineralogical Society of America
Vol. 80, pp. 1059-1064 (1995)
Reederite-(Y), a new sodium rare-earth carbonate mineral with
a unique fluorosulfate anion
Joel D. Grice, Robert A. Gault
Research Division, Canadian Museum of Nature,
P.O. Box 3443, Station D, Ottawa,
Ontario K1P 6P4, Canada

George Y. Chao
Department of Earth Sciences, Carleton University,
Ottawa, Ontario K1S 5B6, Canada

ABSTRACT

Reederite-(Y), ideally, (Na,Mn,Fe)₁₅(Y,REE)₂(CO₃)₉(SO₃F)Cl, is a new mineral from Mont Saint-Hilaire, Quebec. It occurs as blocky, yellow to orange-brown grains up to 2 mm. Associated minerals include trona, shortite, petersenite-(Ce), catapleiite, minor analcime, and manganotychite. The mineral has a vitreous luster and white streak. It is soft (Mohs hardness 3-3.5) and brittle with a conchoidal fracture and perfect {001} cleavage. Reederite-(Y) is uniaxial negative, w 1.548(1) and e 1.537(1).
It is hexagonal, space group P6, a = 8.773(1), c = 10.746(2) Å, and Z = 1. The strongest X-ray powder diffraction lines are [d (Å), I, (hkl)]: ;

2.532, 100, (212)

4.39, 80 (102)

2.774, 80, (113)

2.240, 80, (213)

6.20, 40, (101)

1.657, 40 (116,314,322,410)

2.067, 30, (105,303)

The infrared spectrum is given. An electron microprobe analysis gave:

Na₂O - 34.04

CaO - 0.70

MnO - 1.23

Al₂O₃ - 1.31

Y₂O₃ - 10.24

La₂O₃ - 1.39

Ce₂O₃ - 3.52

Nd₂O₃ - 1.99

Er₂O₃ - 1.19

Dy₂O₃ - 1.39

SO₃ - 5.07

CO₂ - 31.91 (calc)

F - 1.86

Cl - 2.05

-O = F + Cl - 1.24

(plus minor amounts of Fe, Pr, Sm, Gd, and Yb oxides), total 99.14 wt%.
D_meas = 2.91, D_calc = 2.85. The structure has been refined to R = 3.2%. The carbonate layers are thick slabs accommodating (CO₃)^2- groups oriented perpendicular to the {001} layering, the large cation polyhedra, and the Cl^- and (SO₃F)^- anions. The Na atoms adopt a variety of distinct coordinations. This is the first reported natural occurrence of a fluorosulfate anion.

Logo ™