IMA Code

Mrb

	Formula	Name	Family	Number min-max	Isotope mole fraction	State	Relevance
	$Na$	Sodium	element	2		constituent cation	main
	$(SO_4)^{2-}$	Sulfate anion	chemical function	1		anionic radical	main
	$H_2O$	Water	molecule	7		hydration	main

Chemical functions

	Function	Number
	$(SO_4)^{2-}$	1
	$R-OH$	2

Chemical bonds

	Bond	Number
	$-O-H$	2
	$\dddot - \dddot - \dddot - S \dddot - O^{-1/2}$	4

Oxides

Formula	$Na_{2}O$	$SO_{3}$	$H_{2}O$
Mass fraction (%)	19.24	24.85	55.91

Strunz

Class

sulfates - chromates - molybdates - tungstates (07)

Division

sulfates (selenates, etc.) without additional anions, with H2O (07.C)

Family

with only large cations (07.CD)

Code

07.CD.10

Dana

Major class

sulfates, chromates, selenates (VI)

Class

hydrated acid and sulfates (29)

Type

where (A+)2XO4.x(H2O) (29.02)

Group

-Mirabilite- group (29.02.02)

Code

29.02.02.01

Phase type

crystalline

Crystal system

monoclinic

Crystal class

prismatic

Crystal class symbol

2/m (C2h)

Crystal spacegroup

P2(1)/m

Refringence type

biaxial

Refringence sign

negative

Birefringence

0.023

Refraction index $n_{\alpha}$

1.396

Refraction index $n_{\beta}$

1.4103

Refraction index $n_{\gamma}$

1.419

Pure color

colorless

Color

Colorless, White, Yellowish white, Greenish white

Diaphaneity

transparent to opaque

Luster

vitreous

Links

• Wikipedia
• Webmineral database
• Mindat
• Handbook of Mineralogy (Min. Soc. Am)