Chapter 17 The d-block elements (Ⅰ) §17.1 Outline on the d-block elements *§17.2 Titanium Vanadium §17.3 Cr Mo W §17.4 Mn §17.5 Fe Co Ni

§17.1 Outline on the d-block elements 17.1.1 The atom radii and ionization energy of the d-block elements 17.1.2 General physical properties 17.1.3 The chemical properties of the d-block elements 17.1.4 Oxidation numbers of the d- block elements 17.1.5 Colors of the d-block metal ions in solution

17.1.1 The atom radii and ionization energy of the d-block elements 1. The position of the d-block elements in the periodic table

2. The valence electron configurations of the d- block elements 1-10ns1-2;(n-1)d Pd: 10 4d 1-34s23d 54s13d 5-84s23d 104s1-23d 1-25s24d 4-55s14d 55s24d 7-85s14d 105s0-24d 5d1-76s2 5d9-106s1 5d106s0-2 3. The atom radii of the d-block elements

4. The first ionization energy(I1) of d-block elements The overall tendency is that values of I1 become slightly bigger from left → right in a row, while irregular in a group.

17.1.2 General physical properties • High m.p and b.p Tungsten (W) has the highest m.p among the elemental substances • High hardness The hardest metal: Cr • High densities The most dense metal: Os • Good conductor of heat and electricity, and good ductibility(延展性)

A plot showing the trend of melting point of the transition metals 6th row melting points 5th row 4th row A plot showing the trend of melting point of the transition metals

A plot showing changes of density The most dense metal: Os catalysts: Most of transition metals and their compounds have unique catalytic properties, e.g.:Pt, Pd, Fe, Cu,V,…PdCl2,V2O5….are often used as catalyst magnetic: Most of transition metal atoms and their ions have unpaired electrons, therefore have paramagnetic properties; magnetic moment increases with increasing number of unpaired electrons

(M ) (M ) 17.1.3 The chemical properties of the d-block elements 元素 Sc Ti V Cr Mn (M ) 2+ -1.2 (估算值) /M V --- -1.63 -0.90 -1.18 E 可溶该 金属的 酸 元素 HNO3， HF 浓 H2SO4 Ni 稀 HCl H2SO4 等 Zn 热 HCl HF 稀 HCl H2SO4 各种酸 Fe Co Cu (M ) 2+ /M V -0.409 -0.282 -0.236 +0.339 -0.762 E 可溶该 金属的 酸 稀 HCl H2SO4 等 缓慢溶解 在 HCl 等 酸中 稀 HCl H2SO4 等 稀 HCl H2SO4 等 浓HNO3， 热 H2SO4 General trends：The chemical reactivity of metal elements decreases from left to right

E E E E (Zn /Zn ) = −0.762 V E (Cd /Cd ) = −0.402 V Within a group? 10 11 12 2+/Ni)(Ni =－0.2363V E 4th row Ni Cu Zn 2+/Pd)(Pd = +0.92V 5th row Pd Ag Cd E Pt Au Hg 6th row 2+/Pt)(Pt = +1.2V(estimated value估计值) E E (Zn /Zn ) = −0.762 V 2+ E (Cd /Cd ) = −0.402 V 2+ E (Hg /Hg ) = +0.852 V 2+ General trend：The chemical reactivity of metal elements decreases from top to bottom

17.1.4 Oxidation numbers of the d- block elements 1-9ns1-2(n-1)d 10ns1-2(n-1)d -1 d-block elements exhibit variable oxidation numbers. +1 -1 +1 -1 E.g: Mn(CO)5Cl, Mn(CO)5 , NaMn(CO)5. More common ones are designated in red.

17.1.5 Colors of the d-block metal ions in solution Mn (Ⅱ) Fe(Ⅱ) Co(Ⅱ) Ni(Ⅱ) Cu(Ⅱ) Zn(Ⅱ) Fe(III) The transition metal ions in solution appear various colors (why?).

其互补的长波长光的颜色． Color of complex ions 分裂能大小不同，所吸收光子的 频率（波长）就不同，配合物呈 现的颜色就不同．配体场的场强 越强，分裂能越大，d-d跃迁时 吸收的光的能量接越大，即波长 越短，则物质的颜色呈现的是 其互补的长波长光的颜色． 配离子吸收光的能量，范围 包括全部可见光区，因而配 离子一般都有颜色

Complementary relationship between color of a substance and that of adsorbed light by the substance 物质颜色与吸收光颜色的互补关系 物质颜色 黄绿 黄 橙 红 紫红 紫 蓝 绿蓝 吸收光颜色 紫 蓝 绿蓝 蓝绿 绿 黄绿 黄 橙 红 波长/nm 400-450 450-480 480-490 490-500 500-560 560-580 580-600 600-650 650-780

§17.3 Cr Mo W 17.3.1 The elemental substances of Cr, Mo and W 17.3.2 The compounds of chromium

17.3.1 The elemental substances of Cr, Mo and W Group VIB elements：Cr, Mo, W Valence electron configuration： Cr, Mo: 5ns1,(n-1)d W: 46s25d 1. The preparation of elemental Cr (the hardest metal ) It exists in the form of chromite Fe(CrO2)2 (铬铁矿)

Fe(CrO2)2(s) Na2CO3 (s) Na2CrO4(s) Fe2O3 (s) Na2CrO4 Na2Cr2O7 Na2Cr2O7 +3 Fe(CrO2)2(s) Na2CO3 (s) Na2CrO4(s) Fe2O3 (s) H2 O 1000 ℃ ~1300℃ 浸取 O2 ① Na2CrO4 (aq) Na2Cr2O7 (aq) ③ Na2Cr2O7 K2Cr2O7 H2SO4 酸化 ② Al Cr2O3 ④ carbon Cr ① 4Fe(CrO 2 ) 2 + 8Na 2 CO 3 + 7O 2 2Fe 2 O 3 + 8Na 2 CrO 4 + 8CO 2 ② 2Na 2 CrO 4 + H 2SO 4 Na 2 Cr2 O 7 + Na 2SO 4 +H 2 O ③ Na 2 Cr2 O 7 + 2C Cr2 O 3 + Na 2 CO 3 + CO ④ 2Al + Cr2 O 3 2Cr + Al 2 O 3

2. The properties of elemental Cr ① Offwhite, the hardest metal, high m.p and b.p ② Reactive metal, the formation of a layer of oxide protects the metal from further attack ③ Pure metal reacts with acids → Cr + + 2H 2+ Cr + H2 O2 3+ Cr (紫) 2Cr + 2H 2SO 4 (浓) → Cr2 SO 4） + 3SO 2 + H 2 O （ 3 Chromium will be passivated in both hot and cold concentrated nitric acid

Cr 2 O -0.74 • The element potential diagram of Cr EA / V 1.33 Cr -0.41 Cr 2 + -0.91 Cr -0.74 2− 7 3+ Cr 2 O EB / V -0.12 -1.1 -1.4 2− 4 − 4 CrO Cr(OH) -1.3 Cr(OH) 2 Cr

17.3.2 The compounds of chromium Cr2O3 (铬绿) m.p./℃ changes when heated 250℃分解为 198暗红色 Cr2O3与O2 975黄色熔融不分解 color CrO3 (铬酐) K2CrO4 K2Cr2O7 (红矾) 398 橙红色 熔融不分解 Cr2O3 (铬绿) 2330 绿色 不分解 CrCl3·6H2O 83 紫色 失去结晶水 KCr(SO4)2·12H2O 暗紫色 89 失去结晶水

Cr2 O Cr2 O CrO CrO 3+(aq)Cr紫 Cr(OH) 亮绿 2- 7 Cr2 O Different ions of Cr in aqueous solution 2+(aq)Cr color pH for their existence 2- 7 ＜2 Cr2 O 橙红 2- 4 CrO ＞6 黄 2- 4 CrO 3+(aq)Cr紫 酸性 Cr(OH) 亮绿 - 4 强碱 3+(aq)Cr 2+(aq)Cr 蓝 酸性

Δ Cr(OH) Cr H 2 O + Cr2 O 3 (green ) 1.Cr2O3 (chrome green, 铬绿) 4Cr⎯→Preparation： + 3O 2 ⎯ 2Cr2 O 3 Δ (NH 4 ) 2 Cr2 O 7 ⎯ Cr2 O 3 + N 2 + 4H 2 O⎯→ Δ Properties: Cr2 O 3 + 6H ⎯ Cr + 3H 2 O⎯→ + Δ 3+ 3H 2 O + Cr2 O 3 + 2OH → Cr(OH) − − 4 2.Cr(OH)3 (brilliant green) (greyish-green) − (适量)OH − OH 3+ − 4 Cr Cr(OH) Cr(OH)3 (s) + + H H Δ H 2 O + Cr2 O 3 (green )

K ≈ 10 3. Salts of Cr(Ⅲ) ion [Cr(OH)(H2O）] + H5 Cr2 SO4） KCr(SO4）⋅12H2O, CrCl3 （， 32 3+ [Cr(OH)(H2O）] + H5 2+ + • Hydrolysis [Cr(H2O）]6 −4 K ≈ 10 2[Cr(H2O)6 3+] [(H2O)4 Cr(OH)2Cr(H2O)4 +水合Cr离子双聚体 +2H 4+] 2Cr + 3S + 6H 2 O ⎯ Cr(OH）(s) + 3H 2S(g )⎯→ 3 3+ 2− 2Cr + 3CO + 3H 2 O ⎯ 2Cr(OH）(s) + 3CO 2 (g )⎯→ 3 3+ 2- 3 Practically, Cr(H2O)6 not 3+ 3+ Cr when pH < 4

• Reduction ability • Oxidization ability E (Cr2 O / Cr ) = 1.33V 2− 7 3+ Acidic condition： + 2Cr + 3S2O + 7 H 2 O 3+ 2− 8 Cr2O + SO + 14H 2− 7 2− 4 + Ag E (CrO / Cr(OH) ) = −0.12V 2− 4 - 4 Basic condition： 2Cr(OH) + 3H 2 O 2 + 2OH − 4 − 2CrO + 8H 2 O 2− 4 • Oxidization ability 3+ + Zn(s) Cr 2Cr ( blue ) + Zn 2+ 2+ 2+(aq)Cr 3+(aq)Cr

Cr2 O + H 2 O 2HCrO (黄)yellow (橙)Orrange • The Colors of hydrate-isomers of complexes of Cr(Ⅲ) ion [Cr(H 2 O）]Cl 3 purple，[Cr(H 2 O）Cl]Cl 2 ⋅ H 2 O cyan65 [Cr(H 2 O）Cl 2 ]Cl ⋅ 2H 2 O green4 蓝绿色 Cr3+: d2sp3 4.The conversion between Cr2O7 and CrO4 ions 2- 2- • The effect of pH +2−2CrO 4 + 2H (黄)yellow Cr2 O + H 2 O (橙)Orrange 2- predominates ;pH<2：Cr2O7 − 4 2− 7 2HCrO pH>6：CrO4 predominates 2-

• The effect of solubility −7 −12 10 Ksp (Ag 2CrO4 ) =1.1 10 Ksp (Ag2Cr2O7 ) =2.0× × 4Ag + Cr2 O + H 2 O 2+2Ba + Cr2O + H 2O + 2− 7 2Ag2 CrO4 (s, 砖红) + 2H +2BaCrO4 (s, 柠檬黄) +2H + 2Pb + Cr2O + H 2O 2+ 2− 7 2PbCrO4 (s, 黄) + 2H + K2Cr2O7 PbCrO4

5. The oxidization ability of Cr2O7 ion 2−3+E (Cr2 O 7 /Cr ) = 1.33V 2- Cr2 O + 3SO 2− 7 2− 3 + 8H + 3SO + 2Cr + 4H 2 O 2− 4 3+ Cr2 O + 3H 2S + 8H 2− 7 + 3S + 2Cr + 7H 2 O 3+ Cr2 O + 6I + 14H 2− 7 − + 3I 2 + 2Cr 3+ + 7H 2 O K 2 Cr2 O 7 (s) + 14HCl(浓) 3Cl 2 + 2CrCl 3 + 2KCl + 7H 2 O Cr2 O + 6Fe + 14H 2− 7 2+ + 6Fe + 2Cr + 7H 2 O 3+ 3+ Cr2 O + 3Sn 2− 7 2+ + 14H + 3Sn + 2Cr + 7H 2 O 4+ 3+

lotion (洗液)：saturated solution of K2Cr2O7 + K2Cr2O7 and its solution is so stable that is used as stand substance for measuring other substances lotion (洗液)：saturated solution of K2Cr2O7 + concentrated H2SO4 K 2Cr2O7 + H 2SO4 (浓) ⎯ K 2SO4 + 2CrO3 (s) + H 2O⎯→ chromic anhydride(铬酐) (black red, needle)

6. The identification of Cr(Ⅲ) − H 2O 2OH −2−⎯⎯ ⎯→ Cr(OH) 4 ⎯⎯ ⎯ → CrO 4 (yellow)⎯ 3+ Cr (brilliant green) +H H 2O 2 2 − (orange 2CrO(O 2 ) 2 ←⎯ ⎯ ⎯ Cr2 O 7⎯ 戊醇(乙醚) red) blue +6 Cr2 O + 4H 2 O 2 + 2H ⎯ 2CrO(O 2 ) 2 + 5H 2 O⎯→ 2− 7 + 乙醚 → CrO(O ) ⋅ (C H ) O CrO(O 2 ) 2 ⎯⎯⎯2 225 2

Summary： O2，△ △ Cr Cr2O3(s,绿) (NH4)2CrO4(橙黄) OH H+ Cr2+ △ 过量OH Cr3+ - Zn O2 - 过量OH - 氨水或适量OH Cr3+ - Cr(OH)4(亮绿) Cr(OH)3 (灰绿) +H +H H2 O2 Cl2 Br2 - ClO 2+,Sn 2+Fe 2- S2O8 2- SO3, H2 S -(Cl-)I - OH 2- Cr2O7(橙红) - CrO4(黄) 2 +H Ag+ 2+Ba H2 O2 H+ +乙醚 Ag Ba2+ 2+CrO(O2)2 Pb (蓝) Ag2CrO4(s,砖红) BaCrO4(s,柠檬黄) PbCrO4(s,黄) 2+Pb

§17.4 Manganese 17.4.1 The elemental substance of Mn 17.4.2 The compounds of manganese

17.4.1 The elemental substance of Mn Group VIIB elements： Mn(manganese) Tc(technetium) Re(rhenium) 5ns2configuration：(n-1)d Valence electron The existence of manganese：magnesian nigra (MnO2•xH2O) 软锰矿 Preparation of Mn and properties：

KClO3 KOH MnO 2 Mn Preparation of Mn： MnO2 ⋅ xH2O △ 530℃ H2 K2MnO4 ① ② 熔融 水浸 H2 KOH △ 530℃ H2 Mn 3 O 4 ⎯⎯ → MnO⎯ K2MnO4 ③ Al Cl2 中性还原 C Mn MnO 2 KMnO4 ① 3MnO2 + 6KOH + KClO3 3K2 MnO4 + KCl + 3H2O Δ Mn3O4 + O2 ② 3MnO2 ③ 3Mn3O4 + 8Al 9Mn + 4Al2O3

Mn + 2H (稀) ⎯ Mn⎯→ + H2 Mn + 2H 2 O ⎯ Mn(OH) 2 (s) + H 2⎯→ Properties of elemental substance Mn： •White metal, hard and brittle (Mn /Mn) = −1.182V •Reactive metal：E 2+ Mn + 2H (稀) ⎯ Mn⎯→ + 2+ + H2 Mn + 2H 2 O ⎯ Mn(OH) 2 (s) + H 2⎯→ •Reacts with metalloid (such as O and halogens)： Δ 3Mn + 2O 2 ⎯⎯→ Mn 3O 4 Mn + X 2 ⎯ MnX 2 (X ≠ F)⎯→ , Mn + F2 ⎯ MnF4和MnF3⎯→

• Reacts with fused caustic base(苛性碱) in the presence of oxidizing agents： 熔融 2Mn + 4KOH + 3O 2 ⎯⎯⎯→ 2K 2 MnO 4 + 2H 2 O

17.4.2 The compounds of manganese 54s2Mn：3d Valence - ofe Manganese exhibits variable oxidation numbers： from –2 to +7 familiar oxidation number: +7, +6, +4 and +2, …. familiar compounds: KMnO4, K2MnO4, MnO2, MnSO4 and MnCl2

Some important Mn compounds 氧化态 分子式 +7 KMnO4 紫红色或近 乎黑色的晶 体 2.71 +6 K2MnO4 +4 MnO2 +2 MnSO4 7H2O MnCl2 4H2O 黑色无定形 粉末 颜色和状态 暗绿色晶体 肉红色晶体 肉红色晶体 密度/(g cm ) -3 --- 5.03 2.1 2.01 58℃， 200~230℃部 分分解出 HCl,无水 MnCl2 红色 片状，熔点 为 650℃ 54℃时溶于 结晶水中,无 水 MnSO4 为 白色,灼烧变 为 Mn3O4 640~680℃分 解为 Mn3O4、O2 和 K2O 200℃以上分 解为 K2MnO4 , MnO2,O2 熔点/℃ 受热时的变 化 530℃分解为 Mn3O4 和 O2 224.7g L-1 (2MKOH)形 成绿色溶液, 静止或水量 较多时,变为 紫红色 6.4 溶液稀释 至 1:500000 时,仍能看出 颜色 溶解度 /(g/100gH2O) 不溶于水 60(10℃) 72

EB / V The potential diagram of Mn： acidic solt.: E A / V 酸性溶液 1.700 disproportionation reaction? 1.23 −1.18 0.5545 2.27 0.95 1.51 − 4 2− 4 3+ 2+ MnO MnO MnO2 Mn Mn Mn 1.51 EB / V Basic solt. − 0.20 − 0.10 −1.56 0.5545 0.6175 − 4 2− 4 MnO MnO MnO2 Mn(OH)3 Mn(OH)2 Mn 0.5965 -0.0514

Mn(OH) 2 + O 2 ⎯ MnO(OH) 2 (s, 棕黄色)⎯→ 2 二羟氧锰 Compounds of II Mn Hydrolysis of Mn(H2 2+:O) [Mn(H2O)6 2+] [Mn(OH)(H2O)5 ++] +H K = －10.610 无O 2 2+ + 2OH ⎯⎯⎯→ Mn(OH) 2 (s,白) − Mn +4 1 Mn(OH) 2 + O 2 ⎯ MnO(OH) 2 (s, 棕黄色)⎯→ 2 二羟氧锰 MnO(OH)2 + (x − 1)H2O ⎯ MnO2 ⋅ xH2O(s,黑褐色)⎯→ Mn(OH) 2 + 2H ⎯ Mn⎯→ + 2+ + 2H 2 O Deduction：Mn(Ⅱ) is unstable under basic condition

Mn + H 2S + 2NH3 ⎯ MnS(s,肉色) + 2NH⎯→ MnS (carnation, 肉色) + H2S → MnS 2+ Mn Mn + H 2S + 2NH3 ⎯ MnS(s,肉色) + 2NH⎯→ 2+ + 4 MnS + 2HAc ⎯ Mn + H 2S + 2Ac⎯→ 2+ −

Weak reducing ability of 2+:Mn 53d 2Mn + 5NaBiO (s) + 14H ⎯ 2MnO + 5Bi + 5Na + 7H2O⎯→ 3 2+ + − 4 3+ + 2Mn + 5PbO2 (s) + 4H ⎯ 2MnO + 5Pb + 2H2O⎯→ 2+ + − 4 2+ + 2Mn + 5S2O + 8H2O ⎯⎯→ 2MnO + 10SO + 16H⎯ 2+ 2- 8 Ag − 4 2− 4 + 2Mn + 5H5IO6 (s) ⎯ 2MnO + 5HIO3 + 7H2O + 6H⎯→ 2+ − 4 + note：①NaBiO3 is normally used to identify 2+ Mn ②HNO3 is normally used to acidify the solt. ③it is very sensitive whenis very low, 2+ is present, purple colorwhile when excess Mn disappears immediately，because： 2+)c(Mn 2+ + 2MnO + 2H 2 O ⎯ 5MnO 2 + 4H⎯→ − 4 + 3Mn

Compounds of Mn(IV): MnO2 • Black amorphous powder, unsoluble in neither water nor dilute acids 530°C → Mn O + O • Thermal stability：3MnO 2 ⎯⎯ ⎯⎯ 3 42 450°C~500°C MnO 2 + H 2 ⎯⎯ ⎯ ⎯ ⎯ ⎯→ MnO + H 2 O 2+• Strong oxidation ability: EA (MnO 2 /Mn ) = 1.229V MnO 2 + 4HCl(浓) ⎯ Cl 2 + MnCl 2 + 2H 2 O⎯→ 2MnO 2 + 2H 2 SO 4 (浓) ⎯ 2MnSO 4 + O 2 + 2H 2 O⎯→ • Weak reducing ability in basic medium MnO 2 + 2MnO + 4OH ⎯ 3MnO⎯→ 浓碱溶液， pH>13.5 − 4 − 2− 4 + 2H 2 O

Compounds of Mn(VI): K2MnO4 ① Bladder green(暗绿色) crystal； ② It is stable in basic solution under the conditions of pH>13.5； ③ It will disproportionate in aqueous solution 2− 4 + 4H ⎯ MnO 2 + 2MnO + 2H 2 O⎯→ + − 4 3MnO 2− 4 + 2CO 2 ⎯ MnO 2 + 2MnO + 2CO⎯→ − 4 2- 3 3MnO − 0.20 − 0.10 −1.56 0.5545 0.6175 − 4 2− 4 MnO MnO MnO2 Mn(OH)3 Mn(OH)2 Mn 0.5965 -0.0514

Compounds of Mn(VII): KMnO4 ① strong oxidizing agent (black purple crystal) EA(MnO /Mn ) = 1.51V − 4 2+ SO 2- 3 4 I I2 - ClH2S 2- Cl2 S 或SO4 - Fe 3+Fe 2+ Sn 4+Sn 2+ 可氧化物种 产物 Reduced forms of MnO4 vary with acidity of solt.： - 2MnO + 5SO + 6H ⎯ 2Mn + 5SO + 3H2O⎯→ − 4 2− 3 + 2+ 2− 4 2MnO + 3SO + H 2 O ⎯ 2MnO 2 + 3SO + 2OH⎯→ − 4 2− 3 2− 4 - 2MnO + SO + 2OH (浓) ⎯ 2MnO + SO + H 2O⎯→ − 4 2− 3 − 2- 4 2− 4 2MnO + 5H 2C2O 4 + 6H ⎯ 2Mn + 10CO2 + 8H 2O⎯→ − 4 + 2+

under light and the presence of acids ② Unstable under light and the presence of acids 4MnO + 4H (微酸) ⎯ 4MnO 2 + 3O 2 + 2H 2 O⎯→ − 4 + In the presence of bases 2−−− 4MnO 4 + 4OH ⎯ 4MnO 4 + O 2 + 2H 2 O⎯→ heated >220°C → K MnO + MnO (s) + O 2KMnO 4 ⎯⎯ ⎯ ⎯⎯ 2422

Summary： (深肉色) (白色) OH + O2 无 H − OH , O 2 (黑褐) S KClO3 KOH + O H2 CO2 MnS ⋅ nH 2 O (白色) Mn(OH) 2 - OH + O2 + H 无 或 (NH 4 ) 2 S O2 + H − OH , O 2 HAc 2+ Mn (肉色)++ MnO 2 (黑褐) HCl(浓), H 2 SO 4 (浓) (H )(H ) 2NaBiO3 SO 3 - , X − +H 2- O3 S KClO3 + KOH + O 或 2− 8 S2 O H 2 S, H 2 O 2 H2 CO2 PbO 2 2+ Fe (歧化) H 5 IO6 2+ Sn -(浓)+SO 2-OH 3 MnO 紫色 - 4 2- 4 MnO 暗绿 +或CO 2-(歧化)H 3

§17.5 Fe Co Ni 17.5.1 The elemental substances of Fe, Co, Ni 17.5.2 The compounds of Fe, Co and Ni

价电子构型 6 23d 4s 7 23d 4s 8 23d 4s 重要氧化值 +2,+3, (+6) +2,+3,(+5) 17.5.1 The elemental substances of Fe, Co, Ni 8 9 10 Group VIII Fe Ru Co Rh Ni Pd iron group platinum group Os Ir Pt 价电子构型 6 23d 4s 7 23d 4s 8 23d 4s 重要氧化值 +2,+3, (+6) +2,+3,(+5) +2,+3,(+4) Fe Co Ni The highest oxidation number isn’t equal to serial number of the group 最高氧化值不等于族序数。

1. The existence of iron element •Hematite(赤铁矿)：Fe2O3； Magnetite: Fe3O4； •Pyrite(黄铁矿)： FeS2； •Cobaltite(辉钴矿)：CoAsS； •Pentlandite(镍黄铁矿): NiS·FeS； 2. Physical properties of elemental iron • White metal, magnetic material； • The melting points of Fe，Co and Ni are similar

Fe + 4H + NO (较浓） Fe + NO + 2H2O→ 3. The chemical properties of elemental iron • Reacts with dilute acids (Co, Ni react slowly): +2+M + 2H (稀) → M (aq) + H 2 4Fe + 10H + NO (稀, 冷） 4Fe + NH + H2O→ + 2+ + 4 - 3 Fe + 4H + NO (较浓） Fe + NO + 2H2O→ + 3+ - 3 • Reacts with conc. acids: Cold conc. HNO3 can passivate Fe, Co, Ni； Conc. H2SO4 can passivate Fe . Fe + 6H + 3NO (热, 浓） Fe + 3NO 2 + 3H 2 O→ + - 3 3+

Fe + O 2 ⎯⎯ → Fe 2 O 3和Fe3O 4⎯ Co + O 2 ⎯⎯ → Co 3O 4和CoO⎯ 3. React with metalloids •Fe,Co and Ni can react with O2, S, X2 when heated. Fe + O 2 ⎯⎯ → Fe 2 O 3和Fe3O 4⎯ 150℃ Co + O 2 ⎯⎯ → Co 3O 4和CoO⎯ 500℃ Ni + O 2 ⎯⎯ → NiO⎯ 500℃ • Pure Fe, Co, Ni are stable in water and air； 4. Forming carbonyl compounds with CO (与CO形成羰合物): Fe(CO)5，Co2(CO)8，Ni(CO)4

17.5.2 The compounds of Fe,Co and Ni 硫酸亚铁铵 (M o h r 盐 ) (N H 4 ) 2 F e (S O 4 ) 2 · 6 H 2 O 硝酸铁 F e (N O 3 ) 3 · 9 H 2O 氯化亚铁 F e C l2· 4 H 2O Important compound 氯化铁 F e C l3 硫酸亚铁 F e S O 4· 7 H 2O 颜色和 状态 密度 (g ·c m -3 ) 熔 点 /℃ 黑褐色 层状晶体 淡紫色晶 体 透明淡蓝 色晶体 淡绿色晶体 绿色晶体 2 .8 9 8 1 .6 8 1 .9 3 7 1 .8 9 5 ~ 1 .8 9 3 1 .8 7 306 371℃ 时 沸 腾 ， 部分分解， 100℃ 时 已 显 著 挥发，见光还 原 为 F e C l2。 F e C l3· 6 H 2O 37℃ 熔 化 ， 100℃ 挥 发 ， 250℃ 分 解 出 F e 2O 3 等 4 7 .2 - - 在空气中风 化变为白色 粉 末 ， 至 73热 ℃ 时 变 白 ，9 0 ℃时熔融， 250℃ 时 开 始 分解，失去 SO 3 50℃ 时 失 去一部分 H N O 3， 高 温下分解 为 F e 2 O 3 (1 2 5 ℃沸腾) F e C l2· 2 H 2O 在 空 气其中部 分氧化变 为草绿色 受热时 的变化 100℃ 左 右 失 去结晶水 6 4 .5 (1 0 ℃ )易 溶 于乙醇， 不溶于乙 醚 2 6 .5 ， 能 溶 于 甘油，不溶 于乙醇，水 溶液易被氧 化 2 6 .9 (2 0 ℃ )， 在潮湿空气 中和水溶液 中较稳定 溶解度 (g /1 0 0 g H 2O ) (无 水 盐 ) 9 1 .8 ， 也 能 溶 于乙醇、甘油、 乙醚和丙酮中 8 3 .8

The important compounds of Co(Ⅱ) and Ni(Ⅱ) 硝酸镍 Ni(NO3)2 ·6H2O 青绿色晶体 2.05 硫酸钴氯化镍氯化钴 7HCoCl2·6H2O CoSO4· 2O NiCl2·6H2O 硫酸镍 NiSO4·7H2O 颜色和状态 -3密度/(g·cm ) 熔点/℃ 粉红色晶体 1.92 722(无水) 淡紫色晶体 1.924 96~98 草绿色晶体 3.55(无水) 1001(无水) 在干空气中 易风化，在 潮湿空气中 易潮解，在 真空中加热 升华不分解 暗绿色晶体 1.98 57℃时溶于 灼烧时得无 其结晶水 水粉末，无 中，进一步 水 NiSO4 呈 加热失去结 亮黄色，在 晶水，灼烧 空气中吸水 时可得 Ni2O3 96.3，能溶 32(10℃)，不 于乙醇，在 溶于乙醇和 空气中易风 醚中 化或潮解 30~35℃开始 风化，无水 CoCl2 为蓝色 粉末，能升 华 加热时失去 结晶水，灼 热时，也不 易分解 受热时的变化 36.21，易溶 于甲醇，无 水 CoSO4 极 难溶于水 50.4，能溶 于丙酮和乙 醇中 64.2，溶于 乙醇 溶解度

The elemental potential diagram of Fe, Co and Ni 2− 4 3+ 2+ − 0.4089 Fe FeO 1.91 FeEA /V ： 0.769 Fe 3+ 2+ − 0.282 Co 1.95 Co Co 2+ − 0.2363 Ni NiO2 1.68 Ni FeO 0.9 Fe(OH)3 − 0.5468 Fe(OH)2 − 0.8914 Fe EB /V ： 2− 4 Co(OH)2 − 0.73 Co Co(OH) 3 0.17 NiO2 0.49 Ni(OH)2 0.69 Ni

Comparison of redox ability of their halides Oxidation ability 大 小 Fe(Ⅲ) Ni(Ⅲ) 大 Co(Ⅲ) -F FeF3 CoF3 * 小 (350℃ decompose) stability -Cl FeCl3 CoCl3 * reducibility (decompose at r.t.) -Br FeBr3 * * -I * * * 小 大 大 小 Stability

Fe + 3OH → Fe(OH)3 (s, 红棕） Fe(OH)3 + 3HCl ⎯ FeCl3 + 3H 2 O⎯→ 1. Hydroxides II, CoII,(Fe II, FeIII, CoIII,Ni III )Ni O 无 2 Fe + 2OH 2+ − Fe(OH) 2 (s,白) O2 Fe(OH)3 (s,红棕) Fe 2 O 3 ⋅ xH 2 O Fe(OH)3 → 4Fe(OH)2 + O 2 + 2H 2O ⎯ 4Fe(OH)3⎯→ Fe + 3OH → Fe(OH)3 (s, 红棕） 3+ - Fe(OH)3 + 3HCl ⎯ FeCl3 + 3H 2 O⎯→

Co(OH)Cl(s, 蓝) 氯化羟钴(碱式氯化钴) - OH - Cl Co + 2OH ⎯ Co(OH)2 (s, pink)⎯→ 2+ − O2 ⎯⎯→ Co(OH)3 (s, 暗棕色)⎯ Co 2 O 3 ⋅ xH 2 O (慢) → Co(OH)3(brown) + 2Co(OH)2 + Br2 + -2OH -Br + H2O Ni + 2OH → Ni(OH)2 (s, 果绿 ) O2 ⎯⎯ → NiO(OH)(s, black)⎯ 2+ − Strong oxidant such as NaOCl、Br2、Cl2

M(OH)2 + 2 H ⎯ 2M + 2 H 2O M = Fe, Co, Ni⎯→ while Fe(OH)2 only need air to form Fe(OH)3 2M(OH) 2 + ClO + H 2 O ⎯ 2M(OH) 3 + Cl⎯→ − − Reducing ability: Fe(Ⅱ)>Co(Ⅱ)>Ni(Ⅱ) 2M(OH) 3 + 6HCl(浓) ⎯ 2MCl 2 + Cl 2 + 6H 2 O⎯→ React with acids： M(OH)2 + 2 H ⎯ 2M + 2 H 2O M = Fe, Co, Ni⎯→ + 2+ Fe(OH)3 + 3HCl ⎯ FeCl3 + 3H 2 O⎯→ ⎯→ 2Ni2NiO(OH) + 6 H + 4Cl ⎯ + 2+ + Cl 2 ↑ + 4 H 2 O - + 2Cl- 4NiO(OH)+ 8H ⎯⎯⎯→ 4M + O 2 ↑ +6H 2O + 2+ H 2SO 4 ⎯→2Co(OH)3+ 6HCl(浓) ⎯ 2MCl 2 + Cl 2 + 6H 2 O Oxidizing ability order under acidic condition(酸性条件下 氧化性次序)：Fe(OH) < Co(OH) <NiO(OH)

M(OH) 2 + 2NH 3 ⎯ [M(NH 3 ) 6 ]⎯→ Coordinating reaction(配位反应)： 2+ (M=Co,Ni)

① FeCl3 exhibits covalent character 2. Salts of Fe, Co and Ni (1) Halides ① FeCl3 exhibits covalent character Deliquescent(易潮解), Dimer in gas phase 蒸汽中形成双聚分子 ② CoCl2 6H2O off-color silica gel 52.5℃ 90℃ CoCl2 6H2O pink CoCl2 2H2O violet red 120℃ CoCl2 blue CoCl2 H2O bluish violet

(2) The sulfides of Fe(Ⅱ), Co(Ⅱ), Ni(Ⅱ) FeSCoS -18 4×10-21(α) Ksp 6.3×10 -25(β)Insoluble in water 2×10 NiS -19(α)3.2×10 Black: -24(β)1.0×10 soluble in dilute acids -26(γ)2.0×10 2+ + 2NH 4 + H 2S + 2NH 3 ⎯ FeS(s) +⎯→ Fe 2+ + 2NH 4 + H 2S + 2NH 3 ⎯ CoS(s) +⎯→ Co 2+ + 2NH 4 + H 2S + 2NH 3 ⎯ NiS(s) +⎯→ Ni + 2+ FeS + 2H ⎯ H 2S(s) + Fe⎯→ While CoS and NiS may not dissolve in acids due to crystal type conversion CoS, NiS形成后可能会因晶型转变而不再溶于酸

(3) Familiar salts of iron, cobalt, and nickel and some related reactions 雨林木风1 FeCl3 black brown黑褐色，Fe(NO3)3·9H2O lilac淡紫色， FeCl2·4H2O baby blue淡蓝色, FeSO4·7H2O light green淡绿，

不同Fe（III)盐的溶液呈现不同的颜色源自不同的晶体场 幻灯片 62 雨林木风1 不同Fe（III)盐的溶液呈现不同的颜色源自不同的晶体场 webuser, 2010-12-13

(NH4)2Fe(SO4)2·6H2O(Mohr salt) pea green淡绿色， CoSO4·7H2O淡紫色， CoCl2·6H2O pink粉红色， NiCl2·6H2O grass green草绿色, NiSO4·7H2O sap green 暗绿色 Ni(NO3)2·6H2O turquoise青绿色

[ (i). Hydrolysis 淡绿 K 淡紫 K K 3+ ion： 3+ 水合铁离子双聚体 -2.91K =10 2+[Fe(H2O)6] ++H+[Fe(OH)(H2O)5] 淡绿 -9.5=10 K 3+[Fe(H2O)6] 2++H+[Fe(OH)(H2O)5] 淡紫 -3.05=10 K [ 2+Fe(OH)(H2O)5] ++H+[Fe(OH)2(H2O)4] -3.26=10 K 3+ ion： 3+ The further hydrolysis of Fesimilar to Cr 3+4+ + 2H+2[Fe(H2O)6][(H2O)4 Fe(OH)2Fe(H2O)4] 水合铁离子双聚体 -2.91K =10

Fe Fe H 2O H 2O Structure： H 2O H 2O H 2O H 2O H 2OH 2O 3+ ion: Fe(OH)The final hydrolysis product of Fe 3

only occur weak hydrolysis 仅发生微弱的水解。 2+ andCo 2+ Ni only occur weak hydrolysis 仅发生微弱的水解。 　 [Co(OH)(H2O)5 　=10-12.20K [Co(H2O)6 2+ ] ++] + H (pink) 　 [Ni(OH)(H2O)5 [Ni(H2O)6 2+ ] ++] + H -10.64 K =10 (green)

• Redox properties of iron ions 2− 4 3+ 2+ − 0.4089 Fe EA /V : FeO 1.91 Fe 0.769 Fe EB /V : FeO 0.9 Fe(OH)3 − 0.5468 Fe(OH)2 − 0.8914 Fe 2− 4 (O2 /H 2 O) = 1.229V E 2+Fe : reducing agent 2+溶液应加入Fe)(保存Fe 4Fe + O2 + 4H ⎯ 4Fe + 2H2O⎯→ 2+ + 3+ 6Fe + Cr2 O + 14H ⎯ 6Fe + 2Cr + 7 H 2 O⎯→ 2+ 2− 7 + 3+ 3+ 5Fe + MnO + 8H ⎯ 5Fe + Mn⎯→ 2+ − 4 + 3+ 2+ + 4H 2 O

2Fe + Cu ⎯ Cu⎯→ + 2Fe 2Fe + Fe ⎯ 3Fe⎯→ 2Fe + Sn ⎯ Sn⎯→ + 2Fe z1 3+ :Fe medium strength oxidizing agent 2Fe + Cu ⎯ Cu⎯→ 3+ 2+ + 2Fe 2+ 2Fe + Fe ⎯ 3Fe⎯→ 3+ 2+ 2Fe + Sn 3+ 2+ ⎯ Sn⎯→ 4+ + 2Fe 2+ 2Fe + H 2S ⎯ 2Fe + S + 2H⎯→ 3+ 2+ + → 3+ 2Fe + - 2I 2+ 2Fe + I2 2Fe(OH)3 + 3ClO + 4OH ⎯⎯→ − − 2FeO + 3Cl + 5H 2 O 2− 4 − red

工业上常用FeCl3的溶液在铁制品上刻蚀字样，或在铜板上制造印刷电路。 FeCl3溶液也叫做烂板剂。 幻灯片 68 z1 工业上常用FeCl3的溶液在铁制品上刻蚀字样，或在铜板上制造印刷电路。 FeCl3溶液也叫做烂板剂。 zho, 2009-12-23

Co(OH)Cl(s) blue (ii). Coordination reaction in aqueous solution • Ammino compounds +2+Fe + 2NH 3 ⋅ H 2 O ⎯ Fe(OH)2 (s) + 2NH 4⎯→ Fe + 3NH 3 ⋅ H 2 O ⎯ Fe(OH)3 (s) + 3NH⎯→ 3+ + 4 O2 Co + 6NH 3 ⎯ Co(NH )⎯→ 2+ 2+ 3 6 ⎯⎯→ Co(NH )⎯ 3+ 3 6 -Cl NH3 土黄色 red Co(OH)Cl(s) blue Notice 1： Co(OH)Cl + NH + 5NH3 ⎯ Co(NH )⎯→ + 4 2+ 3 6 + H 2 O + Cl − Addition of NH4Cl can promote reaction to right direction by forming Co(NH3)62+; If NH4Cl is added prior to NH3•H2O, you won’t see blue color of Co(OH)Cl.

+ 6NH 3 ⎯ Ni(NH )⎯→ Ni blue Ni 2 (OH) 2 SO 4 Notice 2： NH3 SO4 E (O2 /H 2 O) = 1.229V E (O2 /OH ) = 0.401V - E (Co /Co ) = 1.95V 3+ 2+ E (Co(NH ) /Co(NH ) ) = 0.169V 3+ 3 6 2+ 3 6 4Co(NH ) + O 2 + 2H 2 O ⎯ 4Co(NH ) + 4OH⎯→ 2+ 3 6 3+ 3 6 − 2+ + 6NH 3 ⎯ Ni(NH )⎯→ blue NH3 2- 2+ 3 6 Ni SO4 Ni 2 (OH) 2 SO 4 pale green (不易观察到) 2+ 6 2+ 3 6 Ni(H2O) Ni(NH ) Ni: sp3d2 hybridization

Solid KSCN or NH4SCN is often used in labs for • Thiocyanides Fe + nSCN ⎯ Fe(NCS) (血红)⎯→ 硫氰合铁(III)配离子 H-S-C≡N:硫氰酸 3+ − 3− n n Identification of 3+Fe H-N=C=S: 异硫氰酸 丙酮→ Co(NCS) 2− (天蓝)+ 4SCN ⎯⎯⎯ 4 2+ − Co 四硫氰合钴(Ⅱ)配离子 2+Identification of Co Solid KSCN or NH4SCN is often used in labs for the identification reactions.

Fe(CN) + 3OH ⎯ Fe(OH) 3 (s) + 6CN⎯→ • Cyanides - CN → Fe(CN)4- 2+−Fe + 2CN ⎯ Fe(CN)2 (s) ⎯⎯⎯→⎯ 6 黄 1 4−3−−Fe(CN) 6 + Cl 2 ⎯ Fe(CN) 6 + Cl⎯→ 2 土黄 Cyanides of iron decompose under basic conditions： 4− 6 + 2OH ⎯ Fe(OH) 2 (s) + 6CN⎯→ − − Fe(CN) Fe(CN) + 3OH ⎯ Fe(OH) 3 (s) + 6CN⎯→ Common salts ： 3− 6 − − K4[Fe(CN)6]: yellow prussiate of potash(黄血盐)yellow K3[Fe(CN)6]: red prussiate of potash (赤血盐) red crystal

(iii) Identification of the corresponding ions II/III ions： The structure ofIdentification of Fe Ⅲ (CN) FeⅡ][KFe 6x 2+：(acidic condition)Fe 2+ 3− + + x[Fe(CN)6 ] + xK ⎯⎯→ xFe [KFe(CN)6 Fe]x (s) Turnbull’s blue condition) +3+4−xFe + x[Fe(CN)6 ] + xK ⎯ [KFe(CN)6 Fe]x (s)⎯→ Prussian blue Remember: KSCN also can. 3+：(acidicFe

brown 棕色 3Fe + NO + 4H (conc.H2SO4) → 3Fe + NO + 2H 2 O The “brown circle” exp. can be used to identify NO3 - and NO2 - 3Fe + NO + 4H (conc.H2SO4) → 3Fe + NO + 2H 2 O 2+ + 3+ - 3 3Fe + NO + 4H (HAc)→ 3Fe + NO + 2H 2 O 2+ + 3+ - 2 [Fe(H 2 O) 6 ] + NO → [Fe(NO)(H2 O)5 ] + H 2 O 2+ 2+ brown 棕色 Conc.H2SO4 for NO3-; while HAc for NO2- brown circle 2+ + NO - solutionFe 3

Identification ofion： +−4−2−[Fe(CN)6 ] + 4H + NO3[Fe(CN)5 NO] (红) 2-S + CO 2 + NH + 4 五氰亚硝酰合铁(Ⅱ)酸根 2− 2− 4− +S ⎯ [Fe(CN) 5 NOS] (红紫)⎯→ [Fe(CN) 5 NO] Identification ofion：(弱酸性) 2+4−2Cu + [Fe(CN)6 ] ⎯ Cu 2 [Fe(CN)6 ](s)⎯→ 2+Cu reddish brown Identification of +K ion： 3K + [Co(NO2 ) 6 ] ⎯ K 3 [Co(NO2 ) 6 ](s)(黄色)⎯→ + 3− 六亚硝酸合钴(III)酸钾

• Identification of Ni ion Ni + 2DMG + 2NH3 ⎯ Ni(DMG)2 (s) + 2NH⎯→ 丁二肟 鲜红色 2+ + 4 CH 3 C = NOH H CH 3 C = NOH O O H 3C CH 3 C=N N=C Ni(DMG) 2： Ni Ni: 2 dsp hybridization C=N N=C H 3C CH 3 O O H

summary Identification: Fe(NCS)n3-n 血红 Co(NCS)42- 天蓝 Ni(DMG)2(s,鲜红) Co(NH3)63+红 [KFe(CN)6Fe]x O2 Ni(NH3)62+蓝 Co(NH3)62+黄 Fe2+ H+ NH3H2O NH3H2O Ni2(OH)2SO4浅绿 Fe(OH)2 Co(OH)Cl(s,蓝) NH3H2O NH3H2O NH3H2O 2+(SO 2-) 淡绿Ni 4 淡绿 Co2+(Cl-) 粉红 Fe2+ OH- OH- OH- Ni(OH)2(s,果绿) Fe(OH)2(s,白) Co(OH)2(s,粉红) NaClO O2 NaClO Fe(OH)3(s,红棕) Co(OH)3(s,红棕) NiO(OH)(s,黑) 浓HCl 浓HCl HCl Ni2+ Fe3+ Co2+ Identification: Fe(NCS)n3-n 血红 Co(NCS)42- 天蓝 Ni(DMG)2(s,鲜红) [KFe(CN)6Fe]x(s,蓝)

本章作业(exercises) 中文教材 pp: 603—606: 7, 10, 13, 16, 19, 22, 24 Textbook in English: