diff --git a/frontend/biochem-properties.html b/frontend/biochem-properties.html
index 93516c1..f5e6bdf 100644
--- a/frontend/biochem-properties.html
+++ b/frontend/biochem-properties.html
@@ -480,15 +480,79 @@ function renderCompare() {
         <tr><td class="row-label">Описание</td>${_compare.map(m=>`<td class="mol-val" style="font-size:.7rem;color:#888">${m.description||'—'}</td>`).join('')}</tr>
       </tbody>
     </table></div>`;
+    // график молярных масс + экспорт
+    html += `<div class="compare-chart-wrap" style="margin-top:14px;background:rgba(255,255,255,.03);border:1px solid rgba(255,255,255,.07);border-radius:14px;padding:14px">
+      <div style="display:flex;justify-content:space-between;align-items:center;margin-bottom:8px">
+        <div class="detail-label" style="margin:0">Молярная масса, г/моль</div>
+        <button onclick="exportCompareCSV()" style="height:28px;padding:0 12px;border-radius:8px;border:1.5px solid rgba(255,255,255,.14);background:rgba(255,255,255,.06);color:#aaa;font:700 .72rem Manrope,sans-serif;cursor:pointer">Экспорт CSV</button>
+      </div>
+      <canvas id="cmp-chart" width="600" height="200" style="width:100%;height:auto;display:block"></canvas>
+    </div>`;
   }
 
   area.innerHTML = html;
   // Draw compare canvases
   setTimeout(() => {
     for (const mol of _compare) drawCompareCanvas(mol);
+    if (_compare.length >= 2) drawMassChart();
   }, 0);
 }
 
+// ── Столбчатый график молярных масс ──
+function drawMassChart() {
+  const cvs = document.getElementById('cmp-chart');
+  if (!cvs) return;
+  const W = cvs.width, H = cvs.height, ctx = cvs.getContext('2d');
+  ctx.clearRect(0, 0, W, H);
+  const data = _compare.map(m => ({ label: m.formula, v: molarMass(m.formula), name: m.name_ru }));
+  const maxV = Math.max(...data.map(d => d.v), 1);
+  const padB = 34, padT = 18, padL = 8, padR = 8;
+  const n = data.length, gap = 18;
+  const bw = Math.min(90, (W - padL - padR - gap * (n - 1)) / n);
+  const colors = ['#9B5DE5', '#06D6E0', '#facc15', '#4ade80'];
+  // ось
+  ctx.strokeStyle = 'rgba(255,255,255,.1)'; ctx.lineWidth = 1;
+  ctx.beginPath(); ctx.moveTo(padL, H - padB); ctx.lineTo(W - padR, H - padB); ctx.stroke();
+  const totalW = bw * n + gap * (n - 1);
+  let x = (W - totalW) / 2;
+  data.forEach((d, i) => {
+    const bh = (d.v / maxV) * (H - padB - padT);
+    const y = H - padB - bh;
+    const col = colors[i % colors.length];
+    const grd = ctx.createLinearGradient(0, y, 0, H - padB);
+    grd.addColorStop(0, col); grd.addColorStop(1, col + '55');
+    ctx.fillStyle = grd;
+    ctx.beginPath();
+    if (ctx.roundRect) ctx.roundRect(x, y, bw, bh, 6); else ctx.rect(x, y, bw, bh);
+    ctx.fill();
+    ctx.fillStyle = '#ddd'; ctx.font = '700 11px Manrope,sans-serif'; ctx.textAlign = 'center';
+    ctx.fillText(d.v.toFixed(1), x + bw / 2, y - 5);
+    ctx.fillStyle = '#888'; ctx.font = '600 10px Manrope,sans-serif';
+    ctx.fillText(d.label.length > 10 ? d.label.slice(0, 9) + '…' : d.label, x + bw / 2, H - padB + 14);
+    x += bw + gap;
+  });
+}
+
+// ── Экспорт сравнения в CSV ──
+function exportCompareCSV() {
+  const rows = [['Свойство', ..._compare.map(m => m.name_ru)]];
+  const cell = v => `"${String(v == null ? '—' : v).replace(/"/g, '""')}"`;
+  rows.push(['Формула', ..._compare.map(m => m.formula)]);
+  rows.push(['Молярная масса, г/моль', ..._compare.map(m => { const v = molarMass(m.formula); return v > 0 ? v.toFixed(2) : '—'; })]);
+  rows.push(['Агр. состояние', ..._compare.map(m => getPhysProps(m.formula).state)]);
+  rows.push(['Растворимость', ..._compare.map(m => getPhysProps(m.formula).solubility)]);
+  rows.push(['T кипения', ..._compare.map(m => getPhysProps(m.formula).bp)]);
+  rows.push(['T плавления', ..._compare.map(m => getPhysProps(m.formula).mp)]);
+  rows.push(['Категория', ..._compare.map(m => catLabel(m.category))]);
+  const csv = '' + rows.map(r => r.map(cell).join(',')).join('\r\n');
+  const blob = new Blob([csv], { type: 'text/csv;charset=utf-8' });
+  const a = document.createElement('a');
+  a.href = URL.createObjectURL(blob);
+  a.download = 'сравнение-молекул.csv';
+  a.click();
+  URL.revokeObjectURL(a.href);
+}
+
 // Per-card 3D view state: id -> { on, rotY, anim }
 const _cc3d = {};
 function _stopCC(id) { const s = _cc3d[id]; if (s && s.anim) { cancelAnimationFrame(s.anim); s.anim = null; } }