Chapter 12 2: the alkaline

Physical Properties Metals Halides, , hydroxides, of oxoacids Complex in aqueous Complexes with amido or alkoxy ligands Diagonal relationships

1

http://www.orau.org/PTP/collection/quackcures/radbath.htm

Radium by Gretchen Grove

http://www.rsc.org/chemsoc/visualelements/pages/data/radium_data.html

2 (Mg,Fe)2SiO4 CaCO3:MgCO3

http://mineral.galleries.com/minera ls/carbonat/dolomite/dolomite.htm http://mineral.galleries.com/Minerals/ Silicate/OLIVINE/OLIVINE.htm MgCO3 Celestite

SrSO4

http://mineral.galleries.com/minerals/ carbonat/magnesit/magnesit.htm Relative abundances in the Earth’s http://www.galleries.com/minerals crust of the alkaline earth metals /sulfates/celestit/celestit.htm

Beryllium

•Small size and high charge in Be2+ •Be is the only group 2 element that does not form a stable complex with [EDTA]4-. • compounds tend to be covalent

•Beryllium occurs in the silicate mineral Be3Al2[Si6O18], and and aquamarine.

Beryl Emerald X-ray Window

http://mineral.galleries.com/minerals/silicate/beryl/beryl.htm http://mineral.galleries.com/minerals/GEMSTONE/EMER http://www.berylliumproducts.com/CommercialXray.aspx ALD/Emerald.htm

Be3Al2[Si6O18]

3 Recycling and uses

Calcium Uses

World production of CaO, Ca(OH)2, CaO*MgO, Ca(OH)2*MgO, and Ca(OH)2*Mg(OH)2 is ~125,000 Mt. o -1 CaO(s) + H2O(l)  Ca(OH)2(s) DrH = -65 kJ mol

Ca(OH)2(s) + CO2(g)  CaCO3(s) + H2O(l)

Hoover Dam coccolithophore http://www.esa.int/esaCP/SEMDOG3AR2E_Protecting_1.html

CaF2 + H2SO4  2HF + Ca(HSO4)2

4 Physical properties of the group 2 metals, M, and their ions, M2.

5 Flame Tests

Ca (orange-red, but pale green when viewed through blue glass) Sr (crimson, but biolet when viewed through blue glass) Ba (apple-green)

Radioactive of Sr

http://www.inchem.org/documents/ehc/ehc/e25_5.gif

6 Metals

Be Ca Sr Ba http://www.americanelements.com/

2Be + O2  2 BeO (protective coating)

Mg + 2H2O(g)  Mg(OH)2 + H2 (g)

M(NH3)  M(NH2) + 4NH3 + H2 (M = Ca,Sr, Ba)

2M + O2 –D 2MO

3M + N2 –D M3N2

8M + S8 –D 8MS

M + Cl2 –D MX2

Drying Agents and Desiccants

Drying agents for drying or predrying solvents include

anhydrous MgSO4, CaCl2, CaSO4, Na2SO4, K2CO3, which are hygroscopic. •some can be regenerated by heating •some react irreversibly with

H2O (e.g. Ca, Mg, CaH2)

CaH2 + 2 H2O → Ca(OH)2 + 2 H2

Drying agents for use in desiccators include anhydrous

CaSO4, CaCl2, KOH, P2O5, which are hygroscopic.

7 BeCl2

state polymeric structure

BeCl2 in the gas

2 [Be2Cl6]

Structures of the monomeric group 2 dihalides, MX2

Fluorides are sparingly soluble. -11 MgF2 Ksp = 7.42x10 -10 CaF2 Ksp = 1.46x10 -9 SrF2 Ksp = 4.33x10 -7 BaF2 Ksp = 1.87x10

Slightly more solubility for larger cations

8 [MgBr2(diglyme)(THF)]

Mg Br

Br

Production of ethyne (acetylene)

CaO + 3C ---2300 K  CaC2 + CO CaC2 + 2H2O  Ca(OH)2 + C2H2

[MgBr2(THF)2]

Gypsum plasters

9 Hydroxides, peroxides, salts of oxoacids

2+ + - 2- Be(OH2)4 +2H , +2H2O ------Be(OH)2 -----+2OH  Be(OH)4

MO2  MO + 1/2 O2 (M = Mg, Ca, Sr, Ba) MgO + H2O2  MgO2 (used in ) basic BeCl2  [NO]2[Be(NO3)4]  Be(NO3)2  Be4(m4-O)(m-O2NO)6

[Be(OH2)4][O2CC≡CCO2]

Be bonding in a beryllium complex ,

[Be4((m4-O)(m-O2CMe)6]

2 [Sr(OH2)8] porphyrin chlorophyll a

[Ca {N(SiMe ) } {m-N(SiMe ) } ] 2 3 2 2 3 2 2 Ca9(m3-O)8(m-O)8O20

10 Diagonal relationships – Li-Mg, Be-Al

CaC2 + N2 ---1300 K  CaNCN + C

11 Desulfurization

+ - SO2 + H2O ⇌ H + [HSO3]

+ - + 2- H + [HSO3] + 1/2 O2  2H + SO4

+ 2- 2H + SO4 + Ca(OH)2  CaSO4*2H2O

or

+ 2- 2H + SO4 +H2O + CaCO3  CaSO4*2H2O + CO2

12