Secondary names

Calcium dihydroxide

CAS number

1305-62-0

	Formula	Name	Family	Number min-max	Isotope mole fraction	State	Relevance
	$Ca$	Calcium	element	1		constituent element	main
	$O$	Oxygen	element	1		constituent element	main
	$(OH)^-$	Hydroxide anion	chemical function	1		anionic radical	main

Composition comments

Common impurities: ?

Chemical functions

	Function	Number
	$(OH)^-$	2

Chemical bonds

	Bond	Number
	$O^--H$	1

Oxides

Formula	$CaO$	$H_{2}O$
Mass fraction (%)	975.6	24.31

Strunz

Class

oxides - hydroxides - arsenites (04)

Division

hydroxides (without V or U) (04.F)

Family

Hydroxides with OH, without H2O; sheets of edge-sharing octahedral (04.FE)

Code

04.FE.05

Dana

Major class

oxides and hydroxides (III)

Class

hydroxides and oxides containing hydroxyl (06)

Type

where X++ (OH)2 (06.02)

Group

Brucite group (Rhombohedral: P-3m1) (06.02.01)

Code

06.02.01.04

Phase type

crystalline

Crystal system

trigonal

Crystal class

ditrigonal-scalenohedral

Crystal class symbol

-3m (D3d)

Crystal spacegroup

P-3m1

Crystal sites

Label	Nb	Type	Wp	Specie	Specie coordinence	Specie occupancy	Specie oxidation state
Ca	1	main	1a-3m.	$Ca^{2+}$	trigonal prismatic VI	1.0	2
O	2	main	6i.m.	$O$		1.0	-1
H	6	main	6i.m.	$H$	linear I	0.333

Refringence type

uniaxial

Refringence sign

negative

Birefringence

0.027

Refraction index $n_o$ (w)

1.574

Refraction index $n_e$ (e)

1.547

Pure color

colorless

Color

light yellow

Diaphaneity

transparent

Luster

pearly

Links

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