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Keterangan Umum Unsur |
Nama, Lambang, Nomor atom |
iridium, Ir, 77 |
Seri kimia |
transition metals |
Golongan, Periode, Blok |
9, 6, d |
Penampilan |
silvery white
 |
Massa atom |
192.217(3) g/mol |
Konfigurasi elektron |
[Xe] 4f14 5d7 6s2 |
Jumlah elektron tiap kulit |
2, 8, 18, 32, 15, 2 |
Ciri-ciri fisik |
Fase |
solid |
Densitas (sekitar suhu kamar) |
22.65 g/cm³ |
Densitas cair pada titik lebur |
19 g/cm³ |
Titik lebur |
2719 K
(2446 °C, 4435 °F) |
Titik didih |
4701 K
(4428 °C, 8002 °F) |
Kalor peleburan |
41.12 kJ/mol |
Kalor penguapan |
231.8 kJ/mol |
Kapasitas kalor |
(25 °C) 25.10 J/(mol·K) |
Tekanan uap
P/Pa |
1 |
10 |
100 |
1 k |
10 k |
100 k |
pada T/K |
2713 |
2957 |
3252 |
3614 |
4069 |
4659 |
|
Ciri-ciri atom |
Struktur kristal |
cubic face centered |
Bilangan oksidasi |
2, 3, 4, 6
(mildly basic oxide) |
Elektronegativitas |
2.20 (skala Pauling) |
Energi ionisasi |
pertama: 880 kJ/mol |
ke-2: 1600 kJ/mol |
Jari-jari atom |
135 pm |
Jari-jari atom (terhitung) |
180 pm |
Jari-jari kovalen |
137 pm |
Lain-lain |
Sifat magnetik |
no data |
Resistivitas listrik |
(20 °C) 47.1 nΩ·m |
Konduktivitas termal |
(300 K) 147 W/(m·K) |
Ekspansi termal |
(25 °C) 6.4 µm/(m·K) |
Kecepatan suara (pada wujud kawat) |
(20 °C) 4825 m/s |
Modulus Young |
528 GPa |
Modulus rigiditas |
210 GPa |
Modulus ruah |
320 GPa |
Nisbah Poisson |
0.26 |
Skala kekerasan Mohs |
6.5 |
Kekerasan Vickers |
1760 MPa |
Kekerasan Brinell |
1670 MPa |
Nomor CAS |
7439-88-5 |
Isotop |
iso |
NA |
waktu paruh |
DM |
DE (MeV) |
DP |
189Ir |
syn |
13.2 d |
ε |
0.532 |
189Os |
190Ir |
syn |
11.8 d |
ε |
2.000 |
190Os |
191Ir |
37.3% |
Ir stabil dengan 114 neutron |
192Ir |
syn |
73.83 d |
β |
1.460 |
192Pt |
ε |
1.046 |
192Os |
192mIr |
syn |
241 y |
IT |
0.155 |
192Ir |
193Ir |
62.7% |
Ir stabil dengan 116 neutron |
194Ir |
syn |
19.3 h |
β< |
2.247 |
194Pt |
195Ir |
syn |
2.5 h |
β< |
1.120 |
195Pt |
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Referensi |
Iridium adalah suatu unsur kimia dalam tabel periodik yang memiliki lambang Ir dan nomor atom 77. A dense, very hard, brittle, silvery-white transition metal of the platinum family, iridium is used in high strength alloys that can withstand high temperatures and occurs in natural alloys with platinum or osmium. Iridium is notable for being the most corrosion resistant element known and for its association with the demise of the dinosaurs, in the form of a meteorite strike. It is used in high temperature apparatus, electrical contacts, and as a hardening agent for platinum.